Books give you a lot of information, some of which you will not truly understand for a good while. Experience is huge. Even play money games gain you experience. After you have gained some experience, go back and reread. Do it again and again. At some point, there will be a lot you already comprehend and then you can focus on the bits that are still eluding you.
At base, all books say the same thing: Keep the good hands, dump the garbage and don't play while tilted. Everything else is extra.
I also strongly recommend Full Tilt Academy. The lessons and sessions give a lot of insight into how to play correctly. The tests can land you in freerolls
-- ones that are easier than normal because a lot of people sit out. Don't take a lot of tests each moth -- stretch them out, as you can only gain eligibility for a freeroll the first time. You need money for the challenges, but they also help you learn to play better. The challenges give you a sense of opportunities to be on the lookout for, and get you used to playing them.