Whatever you are negotiating today, present it as a win/win situation with the other person as the clearest winner.
Your negotiating skills are already strong, but to put yourself in an even better position, put the other person first. Whatever it is you are bargaining over today, make it clear to the other person first how this will benefit them. This strengthens your hand as you are presenting yourself as secondary. Show them it's a win/win situation, but do so by making them the biggest winner.