This week we offer a simple yet very effective exercise in breath control. Please note that this exercise should be done according to ones capacity — do not do anything that is beyond your capacity or it may upset and disturb you. If you are not able to breath as slowly or as deeply as you would like, no harm. Just breath as slowly and as deeply as you can and your capacity will increase naturally over time.
The following are the words of Sri Chinmoy:

Try to breathe in as slowly and a quietly as possible, so that if you placed a tiny thread right in front of your nose it would not even move. Then you will see that your meditation will be deep and your mind will be very calm and quiet.

(Source: Meditation: Man-Perfection In God-Satisfaction)

Sri Chinmoy was once asked the question, “I would like to develop better concentration so that I can keep my mind focused on one thought.” The following is Sri Chinmoy’s answer: