I found this article on Alley Insider entitled 5 Things Negotiators Should Never Say by Alan Horowitz (which can be fount at http://www.businessinsider.com/the-worst-things-you-can-say-while-negotiating-2011-2).  I thought that it contained useful tips on things you should avoid in negotiating.  Just remember that for all of these rules there are exceptions.

There are loads of strategies for playing hardball, but whether you're dealing with an employee, a client or an investor, there are some things that should always stay out of the conversation. Inc provided this helpful list on what not to say during negotiations.

1. The word "between." You think it makes you seem flexible, but it really ends up giving whoever you're dealing with an advantage. After all, if you offer a customer a price range of "between $1,000 and $2,000", odds are they'll pick the lower choice.

2. "I think we're close." No matter how exhausted or pressured you feel, avoid these poisonous words. They let the other side know you're more interested in wrapping up talks than getting what you really want.

3. "Why don't you throw out a number?" Research shows that negotiations often end closer to the original offer than what the other party wants.

4. "I'm the final decision maker." Even if you feel like a boss, it's best to make it clear that there's a higher authority that you have to consult before a decision can be made. It'll help you avoid getting cornered. If you own your business, refer to your investors or advisors.

5. "Screw you." Or similar expletives. The best negotiators remain calm under pressure and don't let their emotions show.

For more on these helpful hardball tips, check out Inc.