Originally Posted by Mr Ehrmantraut
For instance, learning basic strategy in blackjack. Playing perfect basic strategy makes blackjack a near 50/50 game. Then, learn to count cards (a lot easier than you probably think to learn.) I mostly use the K-O Preferred system, but there's a K-O Rookie system that is really easy to learn. I can send you the pdf version of the book, if you don't want to buy it.
By learning to count, you sway the edge in your favor. Granted, not by a lot, and you're not going to win millions, as the movie "21" might have you believe, but you'll have the edge. And, over the long haul, that's all that matters.
Poker (no limit hold 'em, fixed limit hold 'em, omaha, stud, etc.)
Sports betting (if you live in Vegas, or play online)
Video Poker - 9/6 Jacks or Better (optimal strategy, max bet)
Full Pay Deuces Wild (if you can find it. Optimal strategy, max bet)
Bonus whoring (Free play coupon, etc.)
Cashing out comp points for cash, meals, rooms, etc.
All ways to make money playing against the house.
Wizardofodds.com and vpfree2.com have some are good places to start learning about video poker.