Regarding books, let me use the example of Harrington on Holdem, and his tourney series (HoH1,2,3).
I've heard they are outdated.....ha!
Thing is with that particular series (and probably any other decent book) is that when you first read it, your game is such that you recognize certain things and only think you recognize others. Re-reading offers new insights since you have internalized much of what you read are are then prepared to actually digest the previously read stuff that you thought you understood, but really didn't.
I think I have read HoH 3 times. I have another book, by Susie Isaacs, with 1000 tips. I have it in my reading room, and read a few tips every day. Total re-reads on this book is probably 5, but each time I read a tip it triggers some new response. Each of those tips is a paragraph about a situation or concept. Beginner to advanced. It is amazing how often I find I have reverted to some beginner flaw while my advanced understanding of the game is much better.
Moral of this blab is to re-read, and restudy, all those things that make sense to you because maybe you didn't get all out of it that you could have.
Other considerations...
Have you found your game yet..in this case meaning have you decided to concentrate on Ring or tourney? Holdem or Omaha? etc. etc. Jumping around different games and formats, while fine in the long run might not be a good way to get comfortable with your game quickly. Also
bankroll considerations need to be addressed. Bankroll Management threads abound, and will always be a profitable read.