Every day, at work and at home, you are involved in dozens of negotiations, big and small. Many people find negotiation difficult because of their desire to please, to come to an agreement, to compromise. We have been taught that win-win is the best possible result, that we need to "get to yes" so that all sides are happy. That's the biggest mistake you can make in negotiations.

The problem with the consensus-based approach to negotiating is that it will get you killed at the deal-making table. Why? Because if you're focused on making another person happy — or on avoiding making that person mad — then you're focusing on the outcome. You can't control the outcome. You can't control how the other person feels about you. However, you can control your actions and behaviour during the negotiation. That's the essence of what I call Systematic Decision-Based Negotiating, or the No System, for short. The No System teaches negotiators to base each action not on emotions but on what has come before in the conversation and what they can control.

Why do I call it the No System? Because no is the best word in a negotiation. If you invite your respected adversary (in this case, your boss) to say no right from the get-go, you will be amazed at how relaxed she becomes during the discussion. If your boss says no to your requests right from the start, that's OK too. Every toddler in the world knows that no is the beginning of a negotiation, not the end of it. Inviting no, hearing no and even saying no yourself can open up the conversation for real give-and-take. That's what negotiation is all about.

The No System teaches ordinary people how to be formidable negotiators. Once you understand the basic principles of the No System, you'll see that they're applicable in any setting and under any circumstance — whether you're trying to get a new job, a raise or promotion, extend a project deadline, or get a colleague in another department to share staff. The next time you're involved in an important negotiation, forget about consensus-building and the outcome for the moment and avoid making the following 10 most common mistakes in negotiations. Heeding these simple dos and don'ts will make your deals much more effective.

1. Don't tell your employer you hope she'll say yes. Instead, start by inviting your boss to say no. Tell her you're comfortable with a no answer and that you want her to be comfortable saying no. This puts her at ease and clears the air. Watch how her ears perk up and her body language relaxes. OK, she's thinking, I have permission to say no. Now let's hear what this employee has to say.