We have to know two things; A, the concept of mitzvoth and their importance and B, what does it mean to be a good Jew. Sounds simple enough. However, aside from knowledge, we must analyze our behavior and see if is actually consistent with the mitzvoth or not. Before and after every action, we must stop and think. Don't let the yetzer hara win you over by keeping you so busy that you have no time to think.