There is more information in this PDF I found of The Freelance Success Book than I can possibly write up in one post, so I recommend checking it out. Better yet: buy the whole thing.

I was actually googling information on how to handle contract negotiation. For more extensive information on it, head to page 48 of the PDF for advice such as:

Tip #2: You Got to Talk the Talk
Editors and publishers deal with contracts everyday. Their companies probably provide seminars on contracts and negotiations. What about you? You've got to understand the terms and clauses in a contract at least as well as the person you're dealing with. This means getting the information you need. The National Writer's Union publishes an excellent book on the subject: the NWU Guide to Book Contracts. Much of the information is also applicable to journalism contracts.