I wouldn't entirely go with Rawls either, because his premises assume that there is already a very balanced tendency for humans to understand and accept what is expected of promoting justice and we know that such is not the case.
To me, however, justice is the proper application of the rules and regulations that have been democratically accepted by members of a community with the purpose of making it a safer place to live. This proper application of rules and regulations should objectively measure the cause and effect of a situation, and determine to a similar extent the consequence that should be placed upon actions.
Personally, I have a bit of trouble with Rawls's idea because the whole idea of social justice seems really difficult to me. I think that the first part of his two part test is fine. To me, that really is what justice is about -- making sure that everyone is treated equally in the eyes of the law.
But when you start getting into ideas of making sure that the social and economic inequalities are arranged right, I think justice becomes impossible to define.
For example, what level of economic equality does each member of our society deserve to have? How do you determine how much economic inequality is enough and how much is too much? I don't see any way to actually answer that.
So my answer is that justice is making sure people are treated equally in the eyes of the law.