Have you ever tried to put yourself in an asana to find that five minutes later you're asked to come out of the position and you've hardly noticed you were in it?
Usually for concentration positions of balance are preferred - as if you don't concentrate on "here and now" on what you are doing at this precise moment in time, you risk falling on your nose. However certain less challenging positions like the tree may have you feeling perfectly balanced whilst your mind wanders around aimlessly. There are two things you can do here - one is to attempt a more challenging balancing asana (in order to favor your concentration) like garudasana (the eagle) or the other is to turn your gaze inward. But what does that MEAN? How do you do it?
I'd say two things are important here;
Use your breathing as a tool to bring you back to the present moment of time - each time your mind heads for a possible future scenario, gently allow your mind to refocus on your in breath and your out breath. If your concentration that day is particularly weak and you desire to run films in your head particularly strong, it may mean having to refocus, redirect yourself to your breathing every couple of seconds or so. And that is fine. The idea is NOT to rid your mind of thoughts but to bring your attention to here and now, again, and again, and again if necessary.
That is think with the movements and sensations of your body rather than with words. This is fundamental. Inner calm and inner chatter are mutually exclusive. You cannot have one WITH the other. So try to let go of the linguistic part of your thinking. Drop the vocabulary. Instead of attending to unspoken words attend and think via sensations, movements, feelings - through your senses.
If you do this whilst in a yoga position you LIVE it rather than executing it. You become the position rather than doing it. It has a whole different feel about it. Try it.
And listening to others?
Have you found that someone is talking to you and you in the meantime have
gone off on your own trail of thought and suddenly you realize that you haven't been following a word of what your friend has been telling you? Or perhaps you are so conscious of the impression you wish to make on a new friend, boss or colleague that this worry has impeded listening and therefore understanding?
Do we really need to learn how to listen? I think for some talking is easy yet listening seems more difficult.
So here are a few tips;
The first thing to do if you really want to listen to someone is to look them directly in the eyes. Take a longer deep out breath to calm your breathing down, let go of your own linguistic thought. Become aware of the information coming through your senses. Allow the words being said to enter your ears and absorb them as if they were simply sounds (obviously your mind will decipher the meaning for you anyway) Simply be open to the sound of what's being said and let the rest just happen. You'll find you have followed perfectly what has been said, you are able to concentrate more, and the "real" you - that comes up with spontaneous comments and questions, arises without any effort.
Another important factor is immobility. When you are looking someone in the eyes concentrate on that, bring all your attention to those eyes. - everything else is superfluous. Allow all movements of your body to slow down and come to a stand still. You will notice that the person talking to you feels more relaxed and feels like what she is saying is of real interest to you. Because it is. You are no longer interpreting and trying to formulate your next phrase before your partner has finished, you are simply enjoying what is being said with no expectations from yourself nor from the other person. Listening becomes enjoyable.
You may say "if I have to concentrate on all of those things how on earth am I going to be able to concentration what is being said?!" Practice. Try to implement one or two of these factors every time someone speaks and you will find that it becomes second nature (for many it is already second nature). You are simply re-educating yourself to listening which was, when you were a child a very spontaneous and immediate act. You simply have to turn these factors into a habit so further on down the line you can do them without having to think about it first. At the beginning it may feel strange, unnatural but if you persist it gets ever easier and more rewarding.
Your "yogic invitation/homework" for the week is to try to really listen to your wife/husband/girlfriend/boyfriend - or the person you feel closest to. Every time he/she speaks, try implement the above; looking directly into their eyes, letting go of linguistic thought, allow (relative) immobility, be open to sound, breathe slowly, quietly calmly and notice the difference.
Not everyone has to re-learn how to listen of course, but it may be useful to be reminded anyway.