A bodhisattva seeks to attain enlightenment in order to work towards the liberation of ALL beings.
The bodhisattva attains buddhahood but chooses NOT to pass into complete Nirvana until he may enlightenment of all beings with him.
The traditional form of practice for bodhisattvas in Mahayana Buddhism is known as the six paramitas or spiritual perfections.
Phase #1: Dana - Perfection of generosity and the readiness to give oneself up to the service of others - charity in the broadest sense.
Phase #2: Shila - Perfection of moral virtue and discipline.
Phase #3: Kshanti - Perfection of patience and forbearance.
Phase #4: Virya - Perfection of effort, vigour, heroism and strength.
Phase #5 :Dhyana - Perfection of contemplation.
Phase #6: Prajna - Perfection of wisdom - the culmination and synthesis of all the other paramitas.