The three jewels of Jainism (Ratna-traya)

Right Perception (Samyak Darsana):
Right perception consists in seeing the true nature of every substances of the universe. Jainism advocates that one should first try to know, comprehend, and understand the nature of reality, one's own self, religious goal, and the path. One should analyze it, examine it, test it, and verify it, and then, if satisfied, be convinced of its truth and efficacy. 

Right Knowledge (Samyak Jnana):
Right knowledge makes us examine in detail the matter brought into the mind by right conviction. Both are mental processes. Right knowledge must be free from three main defects: doubt, delusion, and indefiniteness.

Right Conduct (Samyak Charitrya):
Proper, correct, appropriate, and truly natural conduct of the living being (soul) is known as right conduct. The human being should be free from all impure activities of thought, word, and deed. This will attain the state of perfect equanimity. 

Right faith and right knowledge are required for right conduct, and all are interdependent. 
 

The five great vows (Maha-vratas)

In order to attain right knowledge, right faith, and right conduct, one must observe the five great vows: 
1. Non-violence - Ahimsa 
2. Truth - Satya 
3. Non-stealing - Achaurya or Asteya 
4. Celibacy/Chastity - Brahmacharya 
5. Non-attachment/Non-possession - Aparigraha 

Non-violence (Ahimsa):
This is the cornerstone of Jainism. Jains believe that as all living beings are equal, no living being has a right to harm, injure, or kill any other living being, including animals, insects, and plants.

Truth (Satya):
To speak the truth requires moral courage. Only those who have conquered greed, fear, anger, jealousy, ego, frivolity, etc., can speak the truth. Jainism insists that one should not only refrain from falsehood, but should always speak the truth which should be wholesome and pleasant. One should remain silent if the truth causes pain, hurt, anger, or death of any living being. 

Non-stealing (Achaurya or Asteya):
Stealing consists of taking another's property without his consent, or by unjust or immoral methods. Further, one should not take anything which does not belong to him. It does not entitle one to take away a thing which may be lying unattended or unclaimed. One should observe this vow very strictly, and should not touch even a worthless thing which does not belong to him. 

Celibacy / Chastity (Brahmacharya):
Total abstinence from sensual pleasure is called celibacy. Sensual pleasure is an infatuating force which sets aside all virtues and reason at the time of indulgence. 

Non-attachment / Non-possession (Aparigraha):
Jainism believes that the more worldly wealth a person possesses, the more he is likely to commit sin to acquire the possession, and in a long run he may be more unhappy. The worldly wealth creates attachments which will continuously result in greed, jealousy, selfishness, ego, hatred, violence, etc. 

These five vows are to be observed strictly and entirely by the monks and nuns. Partial observance is laid down for the householders with additional seven vows.