Patanjali systematically divided the spiritual path in eight stages.

They are Yama, Niyama, Asana, Pranayama, Pratyahara, Dharana, Dhyana and Samadhi.
It is a systematic layered approach to Yoga. Without the perfection in previous step, one cannot get perfection in next step.

Remember: God breathes through all, so be good to all. Everyone is unborn, so don't engage in weighing you are greater than someone else and vice-versa. Look at everyone as equal and creation of God.

 

Yama
Purification of one’s nature.
It consists of Non-violence (Ahimsa), Truthfulness (Satya), Non-stealing (Asteya), Continence (Brahmacharya) and Non-possessiveness (Apraigraha) at both physical and mental levels.
This shall be followed in all walks of life.


Niyama
Observation of the following (rules)
Purity (Sauch), Contentment (Santosh), Austerity (Tapas), Study of one’s own Self (Svadhyaya), Surrender to the will of God (Ishvarapranidhana)


Asana
      Refer to: http://www.sivananda.org/teachings/asana/exercise.html