Sometimes I find that just rereading the books, with a notepad in hand, and just writing down what comes to mind, helps me activate the materials. I try and rephrase things in my own words and do a lot of mind mapping.
For NLP materials, I try and apply the materials and then journal about what I experience. Alex suggested in a forum, that it is important to know what you really want to get out of the books you are reading.
I also find this most helpful.
