Fix your mind at the Lotus Feet of Lord Hari. Then rotate the mind on His silk-cloth (Pitambara), Srivatsa, Kaustubha gem on His chest, bracelets on His arm, ear-rings, crown on the head; then conch, disc, mace and lotus, on His hands and then come to His feet. Repeat the process again and again. Think of His attributes also. In this way you can do Dhyana on Krishna, Rama or Siva.
Uddhava asked: "In what form and with what rites should the devotee think of You? Please inform me of the same fully. " Sri Krishna said: "Seated comfortably in a seat neither high nor low, keeping the hands near the body unmoved, control the eye from wandering outwards. (Fix it on the tip of the nose to prevent distraction). Control the breath by taking it through one nostril and letting it out through the other and vice versa. Control the senses. Pronounce the letter OM continuously and with deep devotion both while inhaling and exhaling.
"The above practice daily at the three periods (morning, noon and dusk) will enable the Jiva to get perfect control of breath within a month. Imagine in the heart the lotus flower with its petals as seat, and fancy the sun, moon and fire to be the three lights, at their proper places. Concentrate your mind and imagine My present form as seated in the flower, with calm, dignified, smiling face, the cheeks resplendent with the lustre of the gold ear-rings; of beautiful neck, of sky colour, wearing a white cloth of spotless purity, with the ornament Srivatsa and the Goddess Lakshmi on the chest. With the weapons and other usual appendages, Chakra, mace, conch and lotus flower in My four hands, My feet shining with diamonds; with the splendour of the various ornaments on My body, crown, Kaustubha (diamond) on the chest, waist-ring, and the amulet at the shoulder, overflowing with grace towards My devotees.
"Run your fancy over the whole form till you complete all the details and then fix your mind on the same without thinking of anything else. By thus looking at the form and fixing the mind from wandering elsewhere, the face will gradually wear an ecstatic look. When thus the mind oblivious of everything else (forgetting even the triple differences, conscious at the starting point viz. , the person concentrating the mind, the form on which the mind is concentrated and the act of concentration) gets fixed in concentration of My form (Dhyeyam), the Jiva becomes completely merged in Me (in the Turiya or conscious Anandic ecstatic state), just as a ball of fire gets merged in a big bonfire. By constant practice of this Samadhi or ecstasy the Jiva very soon gets rid of all delusion caused by diversity and attains bliss. "