1. Not aiming high enough. If you don’t ask, you don’t get. In other words, ask for more than you expect, or you’ll get less than you deserve.
2. Doing their job. Once you make an offer, wait. The other side has three choices: accept it, reject it, or make a counter-offer, which means you can negotiate some more. If you better your offer before the other side answers, you are giving away the store. They will label you a wimp, and then wait for the perfect moment to really start grinding you down.
3. Not knowing what you want. Do your homework. Don’t waste your opponent’s time. Put together a checklist (for your eyes only, of course) of what you must have, what you would like to have and what you can do without.
4. Making concessions before you’ve seen all the demands. If you want to be sucker punched, make concessions piece meal. Not only will your opponents hound you for more, they will out-leverage you with an 11th-hour demand you cannot refuse. Get demands out in the open first, then get them in writing. Once you have a bird’s-eye view of the battlefield, you can make concessions, but only if your opponent takes some demands off the table too.
5. Not flinching. If there is one negotiating tactic you should master, it’s the flinch. Open any book about negotiation, and you’ll see this on the first page: never accept the first offer.