Books are good if you haven't read any yet. Most of them are very very similar. If you were to read 50 of them I'm pretty sure you would wish you didn't read 40 of them.
I keep hearing that they are out of date, but the game is the same. If you are playing low stakes, noobies don't suddenly do better than you after reading a book on poker no matter what book you read.
And if you are playing at the top, no book is going to help you as they have probably read every book you have and more. If you are playing by a books lessons you are also quite predictable and easy to beat for a pro player. It's best to come up with your own strategies and be unique as long as you have a grasp of the fundamentals and still use some common sense.
Learning by watching isn't always the best idea if you already don't know how to play reasonably well because if you think they are making a certain move for one reason and they have a different reason and you try to copy their plays yourself you may be making some pretty huge mistakes. They also don't always play well.
The best way to learn is play as many hands as you can at a limit that doesn't hurt you and play to win every time. The more situations you see and experience you have, the better you will become. Whenever you lose think about what you could have done differently to not lose and then ask yourself would making that change be good if you were to take 5 million hands of play and modify your play?
Also pay attention to the game while you are playing even when you aren't in a hand. When the game starts to feel like a game you would like to watch and you are interested in it, then you will naturally do much better and observe more details that may help your win rate.
