I started trying to think of a list, and wrote something down, and discovered I had just described my Al-Anon group.
I agree with Cyranoak's post, first we need to focus on having a good relationship with ourselves. Once we know how to treat ourselves well, then we know the great balance in relationships between ourselves and others.
After that, make some great new friends, if you're still nervous. Great friends are valuable and irreplaceable anyway, and yet they're more informal than the average "dating" relationship - especially if you're like me and commit too early.
And you can have as many friends as you want at the same time! Nobody gets jealous, and right now, after XABF? I am a great fan of relationships where there's no chance of anyone becoming jealous, especially over stupid things (like having friends).