Be your own best friend first. Learn how to respect yourself. If you can't respect yourself, then you can't respect others. Decide what boundaries are important to you and respect them. Not only is this healthy for you, but you'll also get enough practice and experience so that you'll be familiar in this area when respecting other people's boundaries. Understand what values are important to you and stick by them. Seek out others who honor those values because you'll only end up hurting yourself and possibly others if those people don't have the same values as you.