Sit in a comfortable chair and see how still you can keep. This
is not as easy as it seems. You will have to center your
attention on sitting still. Watch and see that you are not making
any involuntary muscular movements. By a little practice you will
find you are able to sit still without a movement of the muscles
for fifteen minutes. At first I advise sitting in a relaxed
position for five minutes. After you are able to keep perfectly
still, increase the time to ten minutes and then to fifteen. This
is as long as it is necessary. But never strain yourself to keep
still. You must be relaxed completely. You will find this habit
of relaxing is very good.