1. Do your level best to get something you really, really like.
2. Make a promise to yourself—set a time goal in order to limit the time you might waste shopping and the money you might waste buying successive iterations of the same item. The best experiences I've had with new cameras were when I invested in exactly what I wanted and promised myself in advance that I'm going to commit to it for a certain period of time. I committed to the M6 for one year, and used it for nearly three; the OM-4T for three years, and used it for nearly five. Both experiences were great—very focused on pictures as opposed to gear. It's fun to shop, but it's crucial to stop.
3. While you own something, no matter what it is, use it as hard as you can and enjoy it.