If you are reading this article, you've probably played your house game or two, maybe some online Texas Hold Em. You are also researching ways to improve at poker. Texas Hold Em is an easy game to understand, but very complex, which you will find the more you play.
All books is going to be linked after the article
If playing in money games, you have access to Phil Gordon's Little Green Book and read it. After you finish, Harrington on Cash Games 1 and 2. While you're reading, it's also advisable to be playing online, preferable somewhere cheap. Once you have gotten the hang of these books, read Ryan Fee's guide on 6max. This book is excellent, but utilizes a great deal of short hand you are going to pick-up over the first three books. While you happen to be reading and playing, enroll in the forums on Two Plus Two. Post some hand histories and have some feedback on your game. You can also watch some training videos, some are available at Deuces Cracked.
If you might be playing in tournaments, Harrington on Hold'Em 1, 2, and 3 are perfect substitutes for Harrington on Cash Games 1 and 2.
Reading these books and forums, a lot of shorthand is thrown around. It is not scientific, more of a way for those to share with you common situations. There will seldom certainly be a 100% correct way to try out a hand, it really is more an art form than the usual science. Similar to chess, individuals have numerous playing styles, no one is correct.
Phil Gordon's Little Green Book: Lessons and poker online Teachings in No Limit Texas Hold'em by Phil Gordon
Harrington on Cash Games, Volume I: How to Play No-Limit Hold 'em Cash Games by Dan Harrington
Harrington on Cash Games, Volume II: How to Play No-Limit Hold 'em Cash Games by Dan Harrington
Harrington on Hold 'em Expert Strategy for No Limit Tournaments, Vol. 1: Strategic Play by Dan Harrington
Harrington on Hold 'em Expert Strategy for No Limit Tournaments, Vol. 2: Endgame by Dan Harrington
Harrington on Hold 'em Expert Strategy for No Limit Tournaments, Vol. 3: The Workbook by Dan Harrington