user240: I have read some books and web resources that deal with reaching access concentration and from there the first Jhana. They all used mindfulness of breathing and mentioned but never described 'other methods'.
Methods I have found mentioned were body scanning and metta/loving-kindness meditation.
Now for the question: What other methods are there? And even more important: How to practice them?

user8465: The vipassana practice uses a form of one pointed concentration to enter the jhanas. This the dominant tradition. A very different mechanism is described by Bhante Vimalaramsi, who uses the metta practice in combination with a relax step for dealing with hinderances. Bhante maintains that the combination of metta with the relax step leads to quicker access to deeper states. I have not practiced vipassana but have gotten to the 8th jhana with metta and the relax step. There are videos on youtube where he discusses the specifics, look for "one by one as they occurred" with Bhante Vimalaramsi

user295: 
OP: What other methods are there?

In the context of Buddhist meditation, there are 40 subjects of meditation (Kammaṭṭhāna). These are divided into

Samatha for concentration or mastery over the mind (Samadhi)
Vipassanā for wisdom (Paññā)

Samatha techniques generally use a conceptual object (Nimitta pannatti) as the subject of meditation like discs in the case of Kasina, other beings like in the case of Metta. Samatha has been adopted from contemporary techniques. What is unique to Buddhism is Vipassanā. This can be used to develop wisdom (Paññā) and concentration or mastery over the mind (Samadhi). The object of Vipassanā are real objects (Paramattha Dhammas) corresponding to the classification as nama (mentality) and rupa (materiality) or the classification as citta (a moment of consciousness or a moment of experience), cetasika (mental factors accompanying consciousness), rupa (material phenomena) and nibbana (the unconditioned reality) or the classification as 5 khandha namely rupakkhandha (all rupas), vedanākkhandha (feelings), saññākkhandha (remembrance or perception), saṅkhārakkandha (all cetasikas, except feeling and remembrance) and viññāṇakkhandha (all cittas).
In Buddhism, the practice has 3 folds, which also correspond to a type of meditation:

morality (Śīla) - developed though recollection of morality (Śīla)
mastery over the mind (Samadhi) - developed through Samatha
wisdom (Paññā) - developed through Vipassanā

These methods are also listed in this answer.

OP: How to practice them?

Using any of the above subjects one can develop the Jhana's as follows:

To enter the 1st Jhana practice initial application and sustained application (Vitarka-vicara) on a chosen object. [Paṭhama Jhāna Pañha Sutta]
To enter the 2nd Jhana when one is established in the 1st Jhana drop initial application and sustained application (Vitarka-vicara) but remain focused on the chosen object. [Dutiya Jhāna Pañha Sutta]
To enter into the 3rd Jhana drop zest (Pīti) by being steadying the mind on the chosen object. [Tatiya Jhāna Pañha Sutta]
To enter into the 4th Jhana by dropping happiness (Sukha) with only equanimity (Ekaggata) remaining, still remaining focused on the chosen object. [Catuttha Jhāna Pañha Sutta]
To enter into the 5th Jhana one transcends the perceptions of form, with the disappearance the perceptions of sense-reaction, with non-attention to perceptions of diversity, aware that “Space is infinite,”. [Ākāsânañc’āyatana Pañha Sutta]
To enter into the 6th Jhana one transcends the sphere of infinite space, aware that “Consciousness is infinite,”. [Viññāṇañc’āyatana Pañha Sutta]
To enter into the 7th Jhana one transcends the sphere of infinite consciousness, aware that ‘There is nothing,’. [Ākiñcaññ’āyatana Pañha Sutta]
To enter into the 8th Jhana one transcends the sphere of nothingness, one enters and dwells in the sphere of neither-perception-nor-non-perception. [N’eva,saññā,nâsaññ’āyatana Pañha Sutta]
To enter into the cessation one does not attend to any signs of residual perception in the 8th Jhana. [Animitta Ceto,samādhi Pañha Sutta]


user43: It depends on how you understand the first and second jhanas. If, like me, you take them as glorified descriptions of being able to get yourself in a joyful mood deliberately, then there are bunch of methods.

first, as Buddha himself suggested, by thinking through good discursive sequences. Specifically, if your practice of "guarding the gates" is going well, and your life is all setup in accordance with the eightfold path, and you understand the Three Marks of Existence and the Four Noble's Truths, then you are in good position to reflect at how your mind is now perfectly shielded from negative states. This theme makes for a great topic of vitakka/vicara and is what Buddha himself used.
second, as other teachers taught me, by remembering a place you felt good/strong at and coming back to it in your thoughts.
third, as I did several times, through meditating on love to all humanity (past, present and future!) or on love to God (it does not matter whether God exists, taking it as object of meditation still works).
fourth, as my present teacher teaches me, through dancing to music, while improvising and feeling the rhythm.
fifth, through special yoga poses, like Eagle Posture and Lion Posture.
sixth, supposedly through sexual tantric practices.
seven, once you learn to feel your chakras and deliberately activate them at will, through direct intent.

These are the methods that come to mind. Now, keep in mind that First and Second jhanas, while useful, are traps on the way to Ultimate Realization. So don't get too hung up on always being in a joyful mood.

user18: The Theravada tradition recognizes forty meditation types for obtaining at least access concentration, found scattered throughout the Tipitaka and organized in the commentaries, as follows:
1-10: The Kasinas
These all lead to the four jhānas; they are practiced by creating a disk and focusing on it, while repeating, e.g., "earth, earth..."
1. Earth
2. Water
3. Fire
4. Air
5. Blue
6. Yellow
7. Red
8. White
9. Light
10. Space
11-20: Foulness
These lead to the first jhāna; they are practiced by contemplating a corpse in various states of decay
11. Bloated
12. Livid
13. Festering
14. Cut Up
15. The Gnawed
16. Scattered
17. Hacked and Scattered
18. Bleeding
19. Worm-infested
20. a Skeleton 
21-30: Recollections
Body and Breathing bring jhāna (body only brings the first jhāna, breath brings all four); the other eight bring only access concentration; they are cultivated by reflecting on the object, e.g. "Buddha, Buddha"
21. Buddha
22. Dhamma
23. Sangha
24. Morality
25. Generosity
26. Angels
27. Death
28. Body
29. Breathing
30. Peace
31-34: The Divine Abidings
The first three bring about the first three jhānas; the fourth brings about the fourth jhāna; they are cultivated by taking beings as an object, e.g. "May all beings be happy"
31. Love 
32. Compassion
33. Joy 
34. Equanimity 
35-38: The Immaterial States
These bring about the fourth jhāna; they are cultivated by using the fourth jhāna as a base, then expanding and refining the object
35. Limitless Space
36. Limitless Consciousness
37. Nothingness
38. Neither Perception Nor Non-perception
39. Perception of Repulsiveness in Nutriment
This brings about only access concentration; it is practiced by reflecting on food as one collects and eats it.
40. Defining of The Elements
This brings about only access concentration; it is practiced by breaking the body up into the four elements.
All forty meditation subjects are described and taught in detail in the Visuddhimagga; highly recommended for those interested.

240: <p>I have read some books and web resources that deal with reaching access concentration and from there the first Jhana. They all used <em>mindfulness of breathing</em> and mentioned but never described 'other methods'.
<br>Methods I have found mentioned were <em>body scanning</em> and <em>metta/loving-kindness meditation</em>.</p>

<p>Now for the question: What other methods are there? And even more important: How to practice them?</p>
 8465: <p>The vipassana practice uses a form of one pointed concentration to enter the jhanas. This the dominant tradition. A very different mechanism is described by Bhante Vimalaramsi, who uses the metta practice in combination with a relax step for dealing with hinderances. Bhante maintains that the combination of metta with the relax step leads to quicker access to deeper states. I have not practiced vipassana but have gotten to the 8th jhana with metta and the relax step. There are videos on youtube where he discusses the specifics, look for "one by one as they occurred" with Bhante Vimalaramsi</p>
 295: <blockquote>
  <p><strong>OP: What other methods are there?</strong></p>
</blockquote>

<p>In the context of Buddhist meditation, there are 40 subjects of meditation (<a href="https://en.wikipedia.org/wiki/Kamma%E1%B9%AD%E1%B9%ADh%C4%81na" rel="nofollow noreferrer">Kammaṭṭhāna</a>). These are divided into</p>

<ul>
<li><a href="https://buddhism.stackexchange.com/a/2039/295">Samatha</a> for concentration or mastery over the mind (<a href="https://www.accesstoinsight.org/ptf/dhamma/sacca/sacca4/samma-samadhi/index.html" rel="nofollow noreferrer">Samadhi</a>)</li>
<li><a href="https://en.wikipedia.org/wiki/Vitarka-vicara" rel="nofollow noreferrer">Vipassanā</a> for wisdom (<a href="http://www.themindingcentre.org/dharmafarer/wp-content/uploads/2009/12/24.11-Pathama-Jhana-Panha-S-s40.1-piya.pdf" rel="nofollow noreferrer">Paññā</a>)</li>
</ul>

<p><a href="https://buddhism.stackexchange.com/a/2039/295">Samatha</a> techniques generally use a conceptual object (Nimitta pannatti) as the subject of meditation like discs in the case of Kasina, other beings like in the case of Metta. <a href="https://buddhism.stackexchange.com/a/2039/295">Samatha</a> has been adopted from contemporary techniques. What is unique to Buddhism is <a href="https://en.wikipedia.org/wiki/Vitarka-vicara" rel="nofollow noreferrer">Vipassanā</a>. This can be used to develop wisdom (<a href="http://www.themindingcentre.org/dharmafarer/wp-content/uploads/2009/12/24.11-Pathama-Jhana-Panha-S-s40.1-piya.pdf" rel="nofollow noreferrer">Paññā</a>) and concentration or mastery over the mind (<a href="https://www.accesstoinsight.org/ptf/dhamma/sacca/sacca4/samma-samadhi/index.html" rel="nofollow noreferrer">Samadhi</a>). The object of <a href="https://en.wikipedia.org/wiki/Vitarka-vicara" rel="nofollow noreferrer">Vipassanā</a> are real objects (Paramattha Dhammas) corresponding to the classification as nama (mentality) and rupa (materiality) or the classification as citta (a moment of consciousness or a moment of experience), cetasika (mental factors accompanying consciousness), rupa (material phenomena) and nibbana (the unconditioned reality) or the classification as <a href="https://en.wikipedia.org/wiki/Skandha" rel="nofollow noreferrer">5 khandha</a> namely rupakkhandha (all rupas), vedanākkhandha (feelings), saññākkhandha (remembrance or perception), saṅkhārakkandha (all cetasikas, except feeling and remembrance) and viññāṇakkhandha (all cittas).</p>

<p>In Buddhism, the practice has <a href="http://www.themindingcentre.org/dharmafarer/wp-content/uploads/2009/12/24.12a-Dutiya-Jhana-Panha-S-s40.2-piya.pdf" rel="nofollow noreferrer">3 folds</a>, which also correspond to a type of meditation:</p>

<ul>
<li>morality (<a href="https://en.wikipedia.org/wiki/P%C4%ABti" rel="nofollow noreferrer">Śīla</a>) - developed though recollection of morality (<a href="https://en.wikipedia.org/wiki/P%C4%ABti" rel="nofollow noreferrer">Śīla</a>)</li>
<li>mastery over the mind (<a href="http://www.themindingcentre.org/dharmafarer/wp-content/uploads/2009/12/24.13-Tatiya-Jhana-Panha-S-s40.3-piya.pdf" rel="nofollow noreferrer">Samadhi</a>) - developed through <a href="https://buddhism.stackexchange.com/a/2039/295">Samatha</a></li>
<li>wisdom (<a href="http://www.themindingcentre.org/dharmafarer/wp-content/uploads/2009/12/24.11-Pathama-Jhana-Panha-S-s40.1-piya.pdf" rel="nofollow noreferrer">Paññā</a>) - developed through <a href="https://en.wikipedia.org/wiki/Vitarka-vicara" rel="nofollow noreferrer">Vipassanā</a></li>
</ul>

<p>These methods are also listed in <a href="https://buddhism.stackexchange.com/a/2039/295">this answer</a>.</p>

<blockquote>
  <p><strong>OP: How to practice them?</strong></p>
</blockquote>

<p>Using any of the above subjects one can develop the Jhana's as follows:</p>

<ol>
<li>To enter the 1st Jhana practice initial application and sustained application (<a href="https://en.wikipedia.org/wiki/Vitarka-vicara" rel="nofollow noreferrer">Vitarka-vicara</a>) on a chosen object. [<a href="http://www.themindingcentre.org/dharmafarer/wp-content/uploads/2009/12/24.11-Pathama-Jhana-Panha-S-s40.1-piya.pdf" rel="nofollow noreferrer">Paṭhama Jhāna Pañha Sutta</a>]</li>
<li>To enter the 2nd Jhana when one is established in the 1st Jhana drop initial application and sustained application (<a href="https://en.wikipedia.org/wiki/Vitarka-vicara" rel="nofollow noreferrer">Vitarka-vicara</a>) but remain focused on the chosen object. [<a href="http://www.themindingcentre.org/dharmafarer/wp-content/uploads/2009/12/24.12a-Dutiya-Jhana-Panha-S-s40.2-piya.pdf" rel="nofollow noreferrer">Dutiya Jhāna Pañha Sutta</a>]</li>
<li>To enter into the 3rd Jhana drop zest (<a href="https://en.wikipedia.org/wiki/P%C4%ABti" rel="nofollow noreferrer">Pīti</a>) by being steadying the mind on the chosen object. [<a href="http://www.themindingcentre.org/dharmafarer/wp-content/uploads/2009/12/24.13-Tatiya-Jhana-Panha-S-s40.3-piya.pdf" rel="nofollow noreferrer">Tatiya Jhāna Pañha Sutta</a>]</li>
<li>To enter into the 4th Jhana by dropping happiness (<a href="https://en.wikipedia.org/wiki/Sukha" rel="nofollow noreferrer">Sukha</a>) with only equanimity (<a href="https://en.wikipedia.org/wiki/Ekaggata" rel="nofollow noreferrer">Ekaggata</a>) remaining, still remaining focused on the chosen object. [<a href="http://www.themindingcentre.org/dharmafarer/wp-content/uploads/2009/12/24.14-Catuttha-Jhana-Panha-S-s40.4-piya.pdf" rel="nofollow noreferrer">Catuttha Jhāna Pañha Sutta</a>]</li>
<li>To enter into the 5th Jhana one transcends the perceptions of form, with the disappearance the perceptions of sense-reaction, with non-attention to perceptions of diversity, aware that “Space is infinite,”. [<a href="http://www.themindingcentre.org/dharmafarer/wp-content/uploads/2009/12/24.15-Akasanancayatana-Panha-S-s40.5-piya.pdf" rel="nofollow noreferrer">Ākāsânañc’āyatana Pañha Sutta</a>]</li>
<li>To enter into the 6th Jhana one transcends the sphere of infinite space, aware that “Consciousness is infinite,”. [<a href="http://www.themindingcentre.org/dharmafarer/wp-content/uploads/2009/12/24.16-Vinnanancayatana-Panha-S-s40.6-piya.pdf" rel="nofollow noreferrer">Viññāṇañc’āyatana Pañha Sutta</a>]</li>
<li>To enter into the 7th Jhana one transcends the sphere of infinite consciousness, aware that ‘There is nothing,’. [<a href="http://www.themindingcentre.org/dharmafarer/wp-content/uploads/2009/12/24.17-Akincannayatana-Panha-S-s40.7-piya.pdf" rel="nofollow noreferrer">Ākiñcaññ’āyatana Pañha Sutta</a>]</li>
<li>To enter into the 8th Jhana one transcends the sphere of nothingness, one enters and dwells in the sphere of neither-perception-nor-non-perception. [<a href="http://www.themindingcentre.org/dharmafarer/wp-content/uploads/2009/12/24.18-Nevasannanasannayatana-Panha-S-s40.8-piya.pdf" rel="nofollow noreferrer">N’eva,saññā,nâsaññ’āyatana Pañha Sutta</a>]</li>
<li>To enter into the cessation one does not attend to any signs of residual perception in the 8th Jhana. [<a href="http://www.themindingcentre.org/dharmafarer/wp-content/uploads/2009/12/24.19-Animitta-Cetosamadhi-Panha-S-s40.9-piya.pdf" rel="nofollow noreferrer">Animitta Ceto,samādhi Pañha Sutta</a>]</li>
</ol>
 43: <p>It depends on how you understand the first and second jhanas. If, like me, you take them as glorified descriptions of being able to get yourself in a joyful mood deliberately, then there are bunch of methods.</p>

<ul>
<li>first, as Buddha himself suggested, by thinking through good discursive sequences. Specifically, if your practice of "guarding the gates" is going well, and your life is all setup in accordance with the eightfold path, and you understand the Three Marks of Existence and the Four Noble's Truths, then you are in good position to reflect at how your mind is now perfectly shielded from negative states. This theme makes for a great topic of vitakka/vicara and is what Buddha himself used.</li>
<li>second, as other teachers taught me, by remembering a place you felt good/strong at and coming back to it in your thoughts.</li>
<li>third, as I did several times, through meditating on love to all humanity (past, present and future!) or on love to God (it does not matter whether God exists, taking it as object of meditation still works).</li>
<li>fourth, as my present teacher teaches me, through dancing to music, while improvising and feeling the rhythm.</li>
<li>fifth, through special yoga poses, like Eagle Posture and Lion Posture.</li>
<li>sixth, supposedly through sexual tantric practices.</li>
<li>seven, once you learn to feel your chakras and deliberately activate them at will, through direct intent.</li>
</ul>

<p>These are the methods that come to mind. Now, keep in mind that First and Second jhanas, while useful, are traps on the way to Ultimate Realization. So don't get too hung up on always being in a joyful mood.</p>
 18: <p>The Theravada tradition recognizes forty meditation types for obtaining at least access concentration, found scattered throughout the Tipitaka and organized in the commentaries, as follows:</p>

<p><strong>1-10: The Kasinas</strong></p>

<p><em>These all lead to the four jhānas; they are practiced by creating a disk and focusing on it, while repeating, e.g., "earth, earth..."</em></p>

<p>1. Earth
<br/>2. Water
<br/>3. Fire
<br/>4. Air
<br/>5. Blue
<br/>6. Yellow
<br/>7. Red
<br/>8. White
<br/>9. Light
<br/>10. Space</p>

<p><strong>11-20: Foulness</strong></p>

<p><em>These lead to the first jhāna; they are practiced by contemplating a corpse in various states of decay</em></p>

<p>11. Bloated
<br/>12. Livid
<br/>13. Festering
<br/>14. Cut Up
<br/>15. The Gnawed
<br/>16. Scattered
<br/>17. Hacked and Scattered
<br/>18. Bleeding
<br/>19. Worm-infested
<br/>20. a Skeleton </p>

<p><strong>21-30: Recollections</strong></p>

<p><em>Body and Breathing bring jhāna (body only brings the first jhāna, breath brings all four); the other eight bring only access concentration; they are cultivated by reflecting on the object, e.g. "Buddha, Buddha"</em></p>

<p><br/>21. Buddha
<br/>22. Dhamma
<br/>23. Sangha
<br/>24. Morality
<br/>25. Generosity
<br/>26. Angels
<br/>27. Death
<br/>28. Body
<br/>29. Breathing
<br/>30. Peace</p>

<p><strong>31-34: The Divine Abidings</strong></p>

<p><em>The first three bring about the first three jhānas; the fourth brings about the fourth jhāna; they are cultivated by taking beings as an object, e.g. "May all beings be happy"</em></p>

<p>31. Love 
<br/>32. Compassion
<br/>33. Joy 
<br/>34. Equanimity </p>

<p><strong>35-38: The Immaterial States</strong></p>

<p><em>These bring about the fourth jhāna; they are cultivated by using the fourth jhāna as a base, then expanding and refining the object</em></p>

<p>35. Limitless Space
<br/>36. Limitless Consciousness
<br/>37. Nothingness
<br/>38. Neither Perception Nor Non-perception</p>

<p><strong>39. Perception of Repulsiveness in Nutriment</strong></p>

<p><em>This brings about only access concentration; it is practiced by reflecting on food as one collects and eats it.</em></p>

<p><strong>40. Defining of The Elements</strong></p>

<p><em>This brings about only access concentration; it is practiced by breaking the body up into the four elements.</em></p>

<p>All forty meditation subjects are described and taught in detail in the Visuddhimagga; highly recommended for those interested.</p>
