If a community creates its own laws,what is it responsible for?

"Inside a community there are a number of individuals who belongs to different social and cultural backgrounds. As they live inside a given region or space having an interaction with each other."

Now, if the community decides to create there own law. Then there must be some areas to cover by them, because one can not just make a law and implement it on others. The law must hold some value and should be valid for all reason.

But, here are the few areas and ideas that a community must look for in order to have a better system of law.

Explanation:

Individuals should be treated as equal: Inside a community no specific person, culture or race should be favored while all should be treated as one. As there is no one above the law.
Fair trial system for all: If any person commits a crime he or she should be treated accordingly, and full procedure of trial and court should be there for the situation.
Protection of Individuals rights and property:Inside a community, each individual basic rights and property should be kept protected by the law or the system, in order to maintain a level of protection and harmony inside the community.