The yamas are non-violence, truth, non-stealing, celibacy as in not being enslaved by sex and detachment to oneís possessions.
Niyamas are purity, happiness, penance, self analysis and surrender to God.
Asanas are a set of postures which help one gain control over the body. Patanjali says ĎSthiram sukham asanamí which means a posture is that which one can remain steady and with ease.
After one has gained enough control over the body to remain still in a meditative position for a fair amount of time, one can move on to pranayama, regulating and controlling oneís breath. Pranayama plays the role of clearing the lungs and increasing their capacity and balancing the left and right brains.
Our senses have the tendency to look outward. Our eyes crave for beauty, our nose for good smells, our tongue for tasty food, ears for music and skin for touch. The next step pratyahara, is about turning the senses inwards.
The above five steps are called bahiranga yoga, the yoga for the external body. Once one masters these five stages, one is ready to progress with antaranga yoga, yoga for the inner self.
After the breath and senses are under control, one starts focusing the mind on a single object. The concept is that of a single object but multiple thoughts directed towards the object. This is called Dharna, or concentration.
When one reduces the multiple thoughts to a single thought about a single object, then dharna becomes dhyana. Concentration then evolves into meditation. While dharna takes effort and is somewhat unnatural, dhyana is natural and automatic.
The eighth and final step is when one succeeds in eliminating even the single thought that made up his meditation, and finally only the object remains. This is the stage when one loses awareness of his body and merges with universal consciousness. This is Samadhi, super-consciousness.
In the initial stages, Samadhi is only an experience, and one comes back to normalcy after some time. This is due to residual impurities in the person. When a person manages to remove all traces of ego and any other negativities, he can remain in Samadhi for long durations, and Samadhi evolves from being just an experience to becoming a state of being.
Focusing only on the physical aspects of yoga is like eating a fruit and throwing the seed away instead of planting it. Imagine a state of being so blissful that the pleasure of the tastiest meal, the kick of alcohol or drugs and the ecstasy of sex pale in comparison. Isnít it time to take our sights off the petty things and chase after the ultimate experience?