Try longer. Don't read a book with the assumption that you will derive value from it in the amount of time it takes to simply read all of the words start to finish. You will need to try examples, re-read sections, skip around, ask questions of others, find other sources, etc.

Sometimes it would be nice if life was more like an RPG - reading a book means a few hours ticks by and then you get +1 to your skill of choice - but unfortunately it's not that easy :)