There are others here that can offer more insight, but here's my two cents worth.
experience, experienc, experience.....
The more you play, the better you'll become. You can read any number of books and probably gain a little insight from each of them, but you'll gain alot more from simply playing. One tip that may be useful, try to memorize the ranking of the best pre-flop starting hands, and the betting progression. Learn the %'s of the hand and how to bet them. EX.: don't risk calling a $300 bet on a hand that is 4-1, on a pot that totals $100
Playing for play money on line will also help BUT....some of these jokers that play online (especially for play money) think they are high stakes players and seem to think going "all-in" is a badge of honor. It's rare to find a table without one of these idiots. Plus, because it's play money, several players stay in the pot when they shouldn't. Despite the pitfalls, I think it's valuable to play and learn--even if it means grinding your teeth at some of the ineptitude.
Get some experience, read a little, and dive in. good luck...