The following are the important twenty hints on mediation given by Yogi Sri Swami Sivananda.
1. Have a separate meditation room under lock and key. Never allow anybody to enter the room. Burn incense there. Wash your feet and then enter the room.
2. Retire to a quiet place or room where you do not fear interruption, so that your mind may feel secure and at rest. Of course, the ideal condition cannot always be obtained, in which case you should do the best you can. You should be alone, yourself, in communion with God or Brahman.
3. Get up at 4 a.m. (Brahmamuhurta) and meditate from 4 a.m. to 6 a.m. Have another sitting at night from 7 p.m. to 8 p.m.
4. Keep a picture of your Ishta in the room, and also some religious books, the Gita, the Upanishads, the Yoga Vasistha, the Bhagavata, etc. Spread your asana in front of the picture of your Ishta.
5. Sit in padma, siddha, sukha, or swastika asana. Keep the head, neck and trunk in a straight line. Do not bend either forward of backward.
6. Close your eyes and concentrate gently in the trikuti, the space between the two eyebrows. Lock the fingers.
7. Never wrestle with the mind. Do not use any violent effort in concentration. Relax all the muscles and the nerves. Relax the brain. Gently think of your Ishta (personal God). Slowly repeat your gurumantra with bhava (feeling) and meaning. Still the bubbling mind. Silence the thoughts.
8. Make no violent effort to control the mind, but rather allow it to run along for a while, and exhaust its efforts. It will take advantage of the opportunity and will jump around like an unchained monkey at first, until it gradually slows down and looks to you for orders. It may take some time to tame the mind, but each time you try, it will come around you in a shorter time.
9. Saguna and Nirguna Dhyana: To meditate on a Name and a Form of the Lord is saguna-dhyana. This is concrete meditation. Meditate on any form of God you like, and repeat His Name mentally. This is saguna-dhyana. Or repeat OM mentally and meditate on abstract ideas like Infinity, Eternity, Purity, Consciousness, Truth, Bliss, etc., identifying these with your Self. This is nirguna-dhyana. Stick to one method. In the initial stages, saguna-dhyana alone is suitable for the vast majority of persons.
10. Again and again withdraw the mind from worldly objects when it runs away from the lakshya, and fix it there. This sort of combat will go on for some months.
11. When you meditate on Lord Krishna in the beginning, keep His picture in front of you. Look at it with steady gazing without winking the eyelids. See His feet first, then the yellow silken robe, then the ornaments around his neck, then his face, earrings, crown on the head set with diamonds, then his armlets, bracelets, then his conch, disc, mace and lotus. Then come again to the feet. Now start again the same process. Do this again and again for half an hour. When you feel tired, look steadily at the face only. Do this practice for three months.
12. Then close your eyes and mentally visualise the picture and rotate the mind in different parts, as you did before.
13. You can associate the attributes of God, as omnipotence, omniscience, purity, perfection, etc. during the course of your meditation.
14. If evil thoughts enter your mind, do not use your will-force in driving them. You will only lose your energy. You will only tax your will; you will fatigue yourself. The greater the efforts you make, the more the evil thoughts will return with redoubled force. They will return more quickly, also. The thoughts will become more powerful. Be indifferent. Keep quiet. They will pass away soon. Or, substitute good counter-thoughts (pratipaksha-bhavana method). Or think of the picture of God and the mantra, again and again, forcibly. Or, pray.
15. Never let a day pass without meditation. Be regular and systematic. Take sattvic food. Fruits and milk will help mental focussing. Give up meat, fish, eggs, smoking, liquors, etc.
16. Dash cold water on the face to drive off drowsiness. Stand up for 15 minutes. Tie the tuft of hair on the head with a piece of string, to a nail above. As soon as you begin to doze, the string will pull you up. It will wake you up. It will serve the part of a mother. Or, lean upon an improvised swing for 10 minutes and move yourself to and fro. Do 10 or 20 mild kumbhakas (pranayama). Do sirshasana and mayurasana. Take only milk and fruits at night. By these methods you can combat sleep.
17. Be careful in the selection of your companions. Give up going to talkies. Talk a little. Observe mouna for two hours daily. Do not mix with undesirable persons. Read good, inspiring, religious books. (This is substitute for good company, if you do not get positive good company). Have satsanga. These are all auxiliaries to meditation.
18. Do not shake the body. Keep it as firm as a rock. Breathe slowly. Do not scratch the body every now and then. Have the right mental attitude as taught by your guru.
19. When the mind is tired, do not concentrate. Give it a little rest.
20. When an idea exclusively occupies the mind, it is transformed into an actual physical or mental state. Therefore, if you keep the mind fully occupied with the thought of God alone, you will get into nirvikalpa-samadhi (Superconscious state where there is no mind) very quickly. Therefore exert in right earnest.