user7141: I have heard the last thoughts of a person can define next life.
If so can we somehow define them through practice, so when the time comes they will be as we planned?
Or is there a practice that would cause them to be positive?

user4722: Autopositivity is indeed a great skill, virtue, accomplishment, and in its own way a paradise.  With constant watchfulness and training in the Four Immeasurables (the four Divine Abodes) ones natural and spontaneously occurring thoughts can be patterned and trained to be of a purely helpful and nonharmful nature. 
Essentially we are developing the skill of choosing positive conscious states and being patient with nonpositive states.  Anyway, as mentioned above, the four immeasurables are worthy of your immediate attention and application.  

user471: According to the Dvedhavitakka Sutta, whatever one keeps pursuing with his thoughts, that becomes the inclination of his awareness.
And from my understanding, the last thoughts of this life is based on the "inclination of awareness".
The solution according to the sutta, is the consistency in practice towards reshaping the inclination of awareness towards renunciation, non-ill will and harmlessness.
This can be achieved through the Noble Eightfold Path.

"Whatever a monk keeps pursuing with his thinking & pondering, that
  becomes the inclination of his awareness. If a monk keeps pursuing
  thinking imbued with renunciation, abandoning thinking imbued with
  sensuality, his mind is bent by that thinking imbued with
  renunciation. If a monk keeps pursuing thinking imbued with non-ill
  will, abandoning thinking imbued with ill will, his mind is bent by
  that thinking imbued with non-ill will. If a monk keeps pursuing
  thinking imbued with harmlessness, abandoning thinking imbued with
  harmfulness, his mind is bent by that thinking imbued with
  harmlessness.
"Just as in the last month of the hot season, when all the crops have
  been gathered into the village, a cowherd would look after his cows:
  While resting under the shade of a tree or out in the open, he simply
  keeps himself mindful of 'those cows.' In the same way, I simply kept
  myself mindful of 'those mental qualities.'
  - Dvedhavitakka Sutta

According to this quote by V. F. Gunaratna:

This last thought series is most important since it fashions the
  nature of his next existence, just as the last thought before going to
  sleep can become the first thought on awakening. No extraneous or
  arbitrary power does this for him. He does this for himself
  unconsciously as it were.
It is the most important act of his life, good or bad, that conditions
  the last thought moment of a life. The kamma of this action is called
  garuka kamma or weighty Kamma. In the majority of cases the type of
  act which men habitually perform and for which they have the strongest
  liking becomes the last active thought. The ruling thought in life
  becomes strong at death. This habitual kamma is called acinna kamma.


7141: <p>I have heard the last thoughts of a person can define next life.</p>

<p>If so can we somehow define them through practice, so when the time comes they will be as we planned?</p>

<p>Or is there a practice that would cause them to be positive?</p>
 4722: <p>Autopositivity is indeed a great skill, virtue, accomplishment, and in its own way a paradise.  With constant watchfulness and training in the Four Immeasurables (the four Divine Abodes) ones natural and spontaneously occurring thoughts can be patterned and trained to be of a purely helpful and nonharmful nature. </p>

<p>Essentially we are developing the skill of choosing positive conscious states and being patient with nonpositive states.  Anyway, as mentioned above, the four immeasurables are worthy of your immediate attention and application.  </p>
 471: <p>According to the <a href="http://www.accesstoinsight.org/tipitaka/mn/mn.019.than.html" rel="nofollow">Dvedhavitakka Sutta</a>, whatever one keeps pursuing with his thoughts, that becomes the inclination of his awareness.</p>

<p>And from my understanding, the last thoughts of this life is based on the "inclination of awareness".</p>

<p>The solution according to the sutta, is the consistency in practice towards reshaping the inclination of awareness towards renunciation, non-ill will and harmlessness.</p>

<p>This can be achieved through the <a href="http://www.accesstoinsight.org/lib/authors/bodhi/waytoend.html" rel="nofollow">Noble Eightfold Path</a>.</p>

<blockquote>
  <p>"<strong>Whatever a monk keeps pursuing with his thinking &amp; pondering, that
  becomes the inclination of his awareness</strong>. If a monk keeps pursuing
  thinking imbued with renunciation, abandoning thinking imbued with
  sensuality, his mind is bent by that thinking imbued with
  renunciation. If a monk keeps pursuing thinking imbued with non-ill
  will, abandoning thinking imbued with ill will, his mind is bent by
  that thinking imbued with non-ill will. If a monk keeps pursuing
  thinking imbued with harmlessness, abandoning thinking imbued with
  harmfulness, his mind is bent by that thinking imbued with
  harmlessness.</p>
  
  <p>"Just as in the last month of the hot season, when all the crops have
  been gathered into the village, a cowherd would look after his cows:
  While resting under the shade of a tree or out in the open, he simply
  keeps himself mindful of 'those cows.' In the same way, I simply kept
  myself mindful of 'those mental qualities.'
  - <a href="http://www.accesstoinsight.org/tipitaka/mn/mn.019.than.html" rel="nofollow">Dvedhavitakka Sutta</a></p>
</blockquote>

<p>According to this <a href="http://www.accesstoinsight.org/lib/authors/gunaratna/wheel102.html" rel="nofollow">quote</a> by V. F. Gunaratna:</p>

<blockquote>
  <p>This last thought series is most important since it fashions the
  nature of his next existence, just as the last thought before going to
  sleep can become the first thought on awakening. No extraneous or
  arbitrary power does this for him. He does this for himself
  unconsciously as it were.</p>
  
  <p>It is the most important act of his life, good or bad, that conditions
  the last thought moment of a life. The kamma of this action is called
  <em>garuka kamma</em> or weighty Kamma. In the majority of cases the type of
  act <strong>which men habitually perform and for which they have the strongest
  liking becomes the last active thought</strong>. The ruling thought in life
  becomes strong at death. This habitual kamma is called <em>acinna kamma</em>.</p>
</blockquote>
