Yoga
  The Eight Limbs
8
Samadhi
7
Dhyana
6
Dharana
5
Pratyahara
4
Pranayama
3
Asana
2
Niyama
1
Yama

 
 
(1) Yama
The easiest translation of YAMA is Control .
Control by vigilance by keeping a watchful eye on certain tendencies within us with a view to overcoming them.
Tendency
Practice
Resultant
Aggression 
AHIMSA
Non Harming
Deceit
SATYA
Truthfulness
Stealing 
ASTEYA
 Non-Stealing
Lust 
BRAHMACHARYA
Celibacy
Attachment
APARIGRAHA
Detachment

 

(2) Niyama
SHAUCHA
Cleanliness or purity.
SAMTOSHA
Contentment.
TAPAH
To burn or to purify with fire.
SVADHYAYA
Study and self analysis.
ISHVARA-PRANIDHANA
Devotion to the search for the higher self (ISHVARA).
(3) Asana
Asana means Posture or Seat.
Hatha Yoga is a means of Asana practice which leads to steadiness of the body. 
There are many different Asanas (some texts say 4.5 million, others 86,000), of this vast number only fifteen are of benefit. 
Diligent Asana practice enables one to sit in Padmasana (Lotus Posture) for three hours.
Mastery of ASANA is simply being able to lose awareness of the body without losing consciousness.
Swastikasana
Gomukhasana
Veerasana
Koormasana
Kukkutasana
Uttankoormasana
Dhanurasana
Matsyendrasana
Paschimottanasana
Mayurasana (the peacock pose) 
Shavasana  (the corpse pose) 
Siddhasana
Padmasana
Simhasana
Bhadrasana
(4) Pranayama
Pranayama is the control of Prana. 
Prana is Sanskrit for the sum total of all energy. Yama means control. 
Pranayama is very involved and complex, it relates to controlling the mind by controlling ones breathing in a particular way. 
The exercises are classically called Kumbhaks, and lead to the state of Pranayama which is more of an end than a practice.
KUMBHAK
Aspects of breathing. 
PURAKH
Breathing.
RECHAK
Breathing out.
ANTAR KUMBHAK
Holding the breath in the lungs.
BAHYA KUMBHAK 
Holding the breath out.
KAYVALYA KUMBHAK
Automatic and mental control of the function of the lungs ceases and leads to the suspension of the breath.

    When we breathe in we bring oxygen into the lungs where it is discharged into the arterial blood, then carried to the left ventricle of the heart and pumped via the aorta through the systemic arterial system, to all parts of the body where it is burnt as fuel. 
Once burnt the waste product carbon dioxide is carried via the blood corpuscles through the venal system to the right ventricle of the heart where it is pumped and exchanged by the lungs to be exhaled as a waste product.
From this point of view we breath in to acquire fuel and breathe out to dispense with the waste.
Where the Air Quality is good then we feel good (we are what we breath.)
By using various Breathing techniques it is possible to saturate the blood with oxygen, so the need for breathing slows down until the breath actually suspends Kayvalya Kumbhak. This is an automatic function of the Physical body - with heavy exercise our breathing is deep  - during meditation the breathing is shallow and light.

(5) Pratyahara
Pratyahara is the means to turn the mind away from outside sense stimulation in on itself. 

It is a Withdrawal from the outside world to the inside world. 
We can do this by tuning into our Internal sounds or by concentrating on the inner  light. 
When we become fully absorbed in this,  interesting changes of consciousness will occur.
Pranayama & Asana bring us to a position where instead of the mind focusing on external things, It focuses on itself (Pratyahara).

(6) Dharana

    One of the best applications of Dharana is to observe your perception of light when your eyes are closed. 
First you need to cultivate an awareness of this and in fact look for the light. 
When you discover it try to focus upon it as if you are gazing into infinity through a third eye in your forehead. 
It may take a while before you make much progress because each time you seem to be getting somewhere your physical eyes will refocus or  move and that will distract your awareness.
(7) Dhyana
Dhyana (Contemplation) is the experience of absorption in the object of concentration.
When eventually you manage to stick with your experience it will lead into Dhyana. 
It will seem as if you are the light and that the light is all that there is.
The light will become brighter and brighter.
When you try to find yourself in the experience it will tend to diminish and you will find your concentration inverting and bringing you back to your start point (ie. Dharana).
In Dhyana you are separated from your thoughts and overcome them so your mind is pure enough to involve itself in what ever you focus upon,  Dharana frees you from the thinking processes by focusing upon one thing.
(8) Samadhi
     Samadhi (Meditation) is a sustained on - going experience of pure consciousness untainted by any separate awareness. 
You experience yourself as just pure consciousness, called Sampratnata-Samadhi.
The first stage of Samadhi is an exciting glimpse of the higher planes of existence.
There is a profound sense of the self as a witness in this experience.