Even I don't think books does helps me. It only gives annotated games, and a lot of useful information that you can recall when playing. But will not help you to win the game.
For me the best thing I've done is to analyze the games I played.
And studying various of typical positions such as isolani pawn structure and so on.
Is there any one thing that you did that you noticed you got a ton better after reading/doing? I'm a C class player looking to get better, but so far think I've gotten nothing from any books I've ever read. How about you guys?