user13806: Many people suffer because of an endless mind-thoughts. What is the simplest way to stop overthinking and make the mind still?

user43: TL;DR: "The simplest way to stop overthinking" is to let go of importance.
The way my teacher explained this, some thought-patterns can be seen as quasi-living beings, relying on human carriers for their survival. These thought-patterns (he called them "maras") capture our attention by appealing to our sense of importance. By thinking about them and acting out these thoughts in verbal and physical action, we provide maras (~memes, informational quasi-beings) with sustenance and help them propagate to the new carriers. In some sense the thought-patterns can be seen as mental parasites, feeding on human thought energy, propagating through social- and mass-media and virally from carrier to carrier. Much of our stress and overthinking comes from internalizing the thought-patterns as our own opinions!
Maras work by narrowing the carrier's attention: "this is all-important and nothing else is important". Liberation from maras requires letting go of the sense of importance they use to capture the carrier's attention.
To break through a mara's bubble of narrowed attention, we have to make an effort to deliberately expand our attention: "this is not all-important! Here are some other things that are truly important: A, B, C".
I was also taught some somatic exercises that help re-expanding one's narrowed attention:

Tapping the feet. Lay on your back or sit, and stretch your legs forward. Tap your feet sideways on one another for 5-15 minutes.
Peripheral vision. Move your eyes from side to side and/or roll them, to expand your awareness of the peripheral vision.

In my own experience the most effective technique is to simply recognize a mara as a mara and stop identifying with the thought-pattern it represents. The very act of realizing that a particular thought-pattern with its sense of all-importance is an extraneous construct that we don't have to believe in, strips the mara of its power and brings back equanimity. 

user13709: Wrestling the mind with the mind generally just makes more chaos.  You could torture yourself to death wondering why you are thinking this or that when you should be thinking this or that. What a mess.
Instead, consider the Satipatthana Sutta which starts with the body:

Breathing in long, he discerns, 'I am breathing in long'; or breathing out long, he discerns, 'I am breathing out long.' Or breathing in short, he discerns, 'I am breathing in short'; or breathing out short, he discerns, 'I am breathing out short.' He trains himself, 'I will breathe in sensitive to the entire body.' 

As you do this, you will notice that simply being aware of the breath may result in longer breaths. As this awareness deepens, so will your breath. Oddly, a side effect of this awareness is that overthinking gently evaporates effortlessly.
The sutta continues in this clear, deliberate manner. Eventually it does touch on mind and delusion, but only much later. After body. After feeling.


user-1: As a person with obsessive thought disorder I might shed some light on this issue.
The very fact that you are overthinking is that you are clinging to resolving an issue you believe is of highest importance at the moment, as Andrei Volkov already wrote. 
What you might do is to be mindful of obsessiveness as it comes. Label it "Obsessiveness." and continue with your mindful gate keeping. Don't let scattered thoughts (vicàra) roam freely unnoticed. Try to let only wholesome and directed thoughts (vitakka) free. It is the case of a habit. 
It is mostly the issue that such thoughts of overthinking take on subjects that aren't important or even difficult to solve with calm and clear mind, so along with mindfulness of thoughts please add concentrating on breathing. Do not try to tackle such thoughts in the state of confusion, as you will be like a man standing on the deck of the ship in the middle of the sea storm - you don't want to be out in such conditions, it is far better to keep yourself safe inside the ship and wait for better conditions.
No matter how tempting it is to continue inner chatter or how critical it might seem - let go of the need. As what they say: Don't try to talk with the madman - it is not going to work.
Bonus: Ajahn Sumedho - Let Go, Let Go, Let Go

13806: <p>Many people suffer because of an endless mind-thoughts. What is the simplest way to stop overthinking and make the mind still?</p>
 43: <p>TL;DR: "The simplest way to stop overthinking" is to let go of <em>importance</em>.</p>

<p>The way my teacher explained this, some thought-patterns can be seen as quasi-living beings, relying on human carriers for their survival. These thought-patterns (he called them "maras") capture our attention by appealing to our sense of importance. By thinking about them and acting out these thoughts in verbal and physical action, we provide maras (~memes, informational quasi-beings) with sustenance and help them propagate to the new carriers. In some sense the thought-patterns can be seen as mental parasites, feeding on human thought energy, propagating through social- and mass-media and virally from carrier to carrier. Much of our stress and overthinking comes from internalizing the thought-patterns as our own opinions!</p>

<p>Maras work by narrowing the carrier's attention: "this is all-important and nothing else is important". Liberation from maras requires letting go of the sense of importance they use to capture the carrier's attention.</p>

<p>To break through a mara's bubble of narrowed attention, we have to make an effort to deliberately expand our attention: "this is <em>not</em> all-important! Here are some other things that are <em>truly</em> important: A, B, C".</p>

<p>I was also taught some somatic exercises that help re-expanding one's narrowed attention:</p>

<ul>
<li>Tapping the feet. Lay on your back or sit, and stretch your legs forward. Tap your feet sideways on one another for 5-15 minutes.</li>
<li>Peripheral vision. Move your eyes from side to side and/or roll them, to expand your awareness of the peripheral vision.</li>
</ul>

<p>In my own experience the most effective technique is to simply recognize a mara as a mara and stop identifying with the thought-pattern it represents. The very act of realizing that a particular thought-pattern with its sense of all-importance is an extraneous construct that we don't have to believe in, strips the mara of its power and brings back equanimity. </p>
 13709: <p>Wrestling the mind with the mind generally just makes more chaos.  You could torture yourself to death wondering why you are thinking this or that when you should be thinking this or that. What a mess.</p>

<p>Instead, consider the <a href="https://www.accesstoinsight.org/tipitaka/mn/mn.010.than.html" rel="noreferrer">Satipatthana Sutta</a> which starts with the body:</p>

<blockquote>
  <p><a href="https://www.accesstoinsight.org/tipitaka/mn/mn.010.than.html" rel="noreferrer">Breathing in long, he discerns, 'I am breathing in long'; or breathing out long, he discerns, 'I am breathing out long.' Or breathing in short, he discerns, 'I am breathing in short'; or breathing out short, he discerns, 'I am breathing out short.' He trains himself, 'I will breathe in sensitive to the entire body.'</a> </p>
</blockquote>

<p>As you do this, you will notice that simply being aware of the breath may result in longer breaths. As this awareness deepens, so will your breath. Oddly, a side effect of this awareness is that overthinking gently evaporates effortlessly.</p>

<p>The sutta continues in this clear, deliberate manner. Eventually it does touch on mind and delusion, but only much later. After body. After feeling.</p>

<p></p>
 -1: <p>As a person with obsessive thought disorder I might shed some light on this issue.</p>

<p>The very fact that you are overthinking is that you are clinging to resolving an issue you believe is of highest importance at the moment, as Andrei Volkov already wrote. </p>

<p>What you might do is to be mindful of obsessiveness as it comes. Label it "Obsessiveness." and continue with your mindful gate keeping. Don't let scattered thoughts (vicàra) roam freely unnoticed. Try to let only wholesome and directed thoughts (vitakka) free. It is the case of a habit. </p>

<p>It is mostly the issue that such thoughts of overthinking take on subjects that aren't important or even difficult to solve with calm and clear mind, so along with mindfulness of thoughts please add concentrating on breathing. Do not try to tackle such thoughts in the state of confusion, as you will be like a man standing on the deck of the ship in the middle of the sea storm - you don't want to be out in such conditions, it is far better to keep yourself safe inside the ship and wait for <em>better conditions</em>.</p>

<p>No matter how tempting it is to continue inner chatter or how critical it might seem - let go of the need. As what they say: Don't try to talk with the madman - it is not going to work.</p>

<p>Bonus: <a href="https://www.youtube.com/watch?v=iCvRo7xsDnE" rel="noreferrer">Ajahn Sumedho - Let Go, Let Go, Let Go</a></p>
