Concentration

It almost goes without saying that you should be ready to concentrate when you play poker... almost.

I decided, since I only play good starting hands, that it would be OK to run a Full Tilt poker game in one window while I do some work in another window. My reasoning was that I would just wait for one of the good hands I like to play, then switch gears and earn some money.

The insidious thing is... it worked. At least at first. I quickly won 20 big bets. Then the downside of this plan kicked in. I didn't watch the other players in the other games, so I didn't know who only plays good cards, who only raises with a great hand, and who either bluffs or just plays a bad hand to the showdown. And it cost me. I lost an ace-high flush to a full house, lost two pair to a straight, and just kept on losing. Soon I was down 20 big bets instead of up by that much.

Lesson learned - only play poker when you're prepared to focus on what you are doing. Use the hands that you don't play to learn about your opponents.