Read before you sign
A lot of people think if someone hands them a preprinted contract, there's no point in reading or discussing the terms, because it's a done deal before you start. Nothing could be farther from the truth! While in some instances you have to sign standard terms without discussion to get something you want, more often than you may realize you could get a few changes that might work to your advantage. But you can't very well know what you might want to change if you don't even take the time to read the terms. Go through the contract with a highlighter or, if you don't want to make permanent marks, a pencil. Circle anything you don't understand or don't like.
Evaluate your bargaining position
After you've identified the terms you'd like to change or clarify, look at what the contract will require of you -- and of the other party. Is there anything in your part of the bargain that makes you an attractive "get" for the business? How badly do you need what the contract will give you? Sometimes the bargaining power is lopsided in favor of one side or another. If you're on the lower end, know that you may not get much from negotiations. But you'll never know until you try.
Contact the other side
Go to the other party to ask for clarification of any confusing terms and consideration of your objections. Don't give up if you get initial resistance or if you can't get the person you need to answer your questions right away.
Make your points briefly and respectfully
Understand what you want before you start the conversation so you can state your case clearly, for the most impact. Keep in mind your bargaining power (or lack thereof) and know when you're at the end of the line on a particular point. Start with your list of everything you would want in a perfect world, but know what points you're willing to compromise and what points you can't live without. Don't try to be clever; don't take cheap shots. You'll be more respected, and more likely to get some concessions, if you respect the other side.
Confirm your understanding
When you've reached the end of your negotiations, go back through the terms you've agreed on to summarize your agreement. Send a written confirmation to the other party to be sure you're on the same page. Then make sure your terms are incorporated into the contract form you'll be signing.
Sign the amended agreement
When you're sure the contract has everything you've agreed to include, sign it! If there are terms that have been crossed out on the form, initial and date each one. And when you return a signed copy to the other party, convey your thanks for working with you -- especially if you've won any concessions in terms. Negotiations don't have to be unpleasant; keeping them civil, even cordial, can be the start of a great business relationship!