>> 1. Don't pre-purchase games

>> 2. Wait a couple of weeks for real gamer reviews

I know it's hard to do if everyone you know's playing the latest hotness, but if you can wait a few months, you can usually get the game heavily discounted in one of Steam's (or Humble, Green Man or other Steam key sellers) quarterly sales.

I used to buy my games on release date at or near full price, but these days I try very hard to wait as long as I can for them to get heavily discounted. When you pay much less than full price, the sting is lessened if you chalk up too many hours to get a refund.