Gotta be short-can come back and elaborate later:
1. read the following,
Living Happily Ever After (book)
The Seven Levels of Intimacy (book)
The New Love Without Limits (book)
(click polyamory and read the articles)
2. Get the book Opening Up. It has a LOT of great suggestions for things to consider when creating a contract like this-we got it just for that and found it VERY VERY helpful. There were things that we didn't find pertinent to us-but there were also things which were that we didn't think of too.