Negotiating money of anything
When negotiating the price on a new car or house most people give in far too easily, don't negotiate at all or shoot themselves in the foot buy showing how much they want the product and agreeing to buy it before negotiations even begin.
This is what you shouldn't do
1. Get closed (remember this one when the double glazing man is coming round)- The sales process involves 2 types questions open and closed, open questions give the salesperson and idea of what your looking for so he or she can recommend products that suit your needs, closed questions get your commitment things like did you want the kitchen doors in Oak or Birch when you say Oak you've just given that person commitment without even realising it after you've given him your commitment on handles, worktops, delivery dates, Bob and Bill coming to fit it how are you going to get any money of the price?