Dhyana: The penultimate state of Yoga, a level of bliss experienced through deep meditation.
The seventh limb of Ashtanga Yoga, Dhyana is achieved only after the previous stages are taken care of. Yama (social etiquette), Niyama (personal etiquette), Asana (physical practice), Pranayama (breathing exercise), Pratyahara (withdrawal of senses) and Dharana (concentration) are all stepping stones on the journey to enlightenment.
Quieting the mind can be achieved through focussing on the breath. Meditation is a skill, which requires dedication and practice. Traditionally meditation was done in the lotus position. Not for greater advancement but to prevent the meditator from falling over should they fall asleep.
Try: Breathe in through the nose for a count of four, then hold the breath in for four. Finally, breath out for a count of four. Repeat for five minutes. If this feels ok, try holding the breath out (for a count of four) after the exhale.