I've learned a lot since I signed my first contract. Mostly it's you have to take the good with the bad. Oh, you get angry and may even swear - I do. But it's part of the process. But here are some of the lessons I've learned.
1. Never take one person's word for how a publisher is. They speak only from their experiences. I've heard horrible things about a publisher - only to find them a true delight to work with. I've heard excellent things about a publisher - only to find them a nightmare.
2. Trust your gut or if female your woman's intuition. It will rarely steer you wrong.
3. If you do sign with a publisher and aren't happy - try another one. Publishing books is like finding the perfect resturaunt. Your friend might love resturaunt A - but you have had bad experiences and prefer resturaunt B. Example - my husband loves McDonald's and we have one that we go to all the time. Not that there is anything wrong with anyother McDonald's in town - but we've developed sight recognition with the staff and feel more comfortable there... well at least until there latest remodel and there are no comfortable booths...
4. If you are happy with your publisher - don't expect everyone else to love it.
Bottom line - it is your writing career. You are the captain of that boat - do not give over control to any single publisher, editor or individual. And another cliche that I've learned to appreciate - don't put all your eggs in one basket. Cause if the basket breaks - you have one heck of a mess to clean up.