I. Ask your friend to show you some playing cards. Immediately after the exposure, describe the forms you have seen. Give the number, name, etc., such as king of clubs, ten of spades, queen of diamonds, jack of hearts, etc.
II. Read two or three pages of a book. Then close the book. Now attend to what you have read. Abandon all distracting thoughts. Focus your attention carefully. Allow the mind to associate, classify, group, combine and compare. You will get now a fund of knowledge and information on the subject. Mere skipping over the pages inadvertently is of no use. There are students who read a book within a few hours. If you ask them to reproduce some important points of the book, they will blink. If you attend to the subject on hand very carefully, you will receive clear, strong impression. If the impressions are strong, you will have very good memory.
III. Sit in your favourite meditative pose about one foot from a watch. Concentrate on the 'tik-tik' sound slowly. Whenever the mind runs, again and again try to hear the sound. Just see how long the mind can be fixed continuously on the sound.
IV. Sit again in your favourite Asana. Close your eyes. Close the ears with your thumbs or plug the ears with wax or cotton. Try to hear the Anahata sounds (mystic sounds). You will hear various kinds of sounds such as flute, violin, kettledrum, thunder-storm, conch, bells, the humming of a bee, etc. Try to hear the gross sounds first. Hear only one kind of sound. If the mind runs, you can shift it from gross to subtle, or from subtle to gross. Generally you will hear sounds in your right ears. Occasionally you may hear in your left ear also. But try to stick to the sound of one ear. You will get one-pointedness of mind. This is an easy way to capture the mind, because it is enchanted by the sweet sound, just as a snake is hypnotised by the notes of the snake-charmer.
V. Keep a candle-flame in front of you and try to concentrate on the flame. When you are tired of doing this, close your eyes and try to visualise the flame. Do it for half a minute and increase the time to five or ten minutes according to your taste, temperament and capacity. You will see Rishis and Devatas, when you enter into deep concentration.
VI. In a lying posture, concentrate on the moon. Whenever the mind runs, again and again bring it back to the image of the moon. This exercise is very beneficial in the case of some persons having an emotional temperament.
VII. In the above manner, you can concentrate on any star you may single out from the millions of stars shining above your head.
VIII. Sit by the side of a river where you can hear a roaring sound like "OM." Concentrate on that sound as long as you like. This is very thrilling and inspiring.
IX. Lie on your bed in the open air and concentrate on the blue expansive sky above. Your mind will expand immediately. You will be elevated. The blue sky will remind you of the infinite nature of the Self.
X. Sit in a comfortable posture and concentrate on any one of the numerous abstract virtues such as mercy, compassion, etc. Dwell upon this virtue as long as you can.