Patience, knowing when to pull the trigger, trading? Trading is my favorite way to fill my collection when I can. Sadly I'm to the point where what I need, rare home-brews, most of those folks have what I have. I love upgrading to better than what I have and reselling. I find it a game. MOST of the time. If I had a lot of money, I'd pay a high price for stupid things I don't need like a Videoplexer and the Play Cable.
Really though I've had great fun since I this forum and did the Portland Show.