It is a common misconception, especially in the entertainment industry, that you need to be unreasonably aggressive (in discussions/negotiations) to get things done or to prevent yourself from getting walked on.  I disagree completely.

The best negotiators are the ones who understand their boundaries and leverage and remain emotionally detached.

Boundaries define what is acceptable or unacceptable to you in any given situation.  It is factual, not based on feeling.  Example: If the offer is below your acceptable price you walk away from the deal.

Leverage is measured in facts and information.  Example: If you have a contract that promises 1 case of water and you don’t get it, you have the leverage (in the form of a contract) to politely demand it and the leverage to think the promoter is not worth doing business with if they break the contract.

Remaining emotionally detached means that if someone disagrees with you, you don’t take it personally.  This person is not offending you… they are merely disagreeing with an idea.  See the idea as something separate than you.  Imagine a table in front of you where you both place ideas (like cards) and in negotiating you see if any combination of those cards can work for both of you.

This last part is the hardest for most people but it is the most important for quieting The Jerk within.