First of all, learn how to skim the text, it will help you a lot, trust me. Annotation for everything will make you tired after even ten page readings, so try to make the comments alongside the text ONLY on whatever really matters to the subject you are trying to learn. And one more practice that I find extremely useful, is the following: from the initial stage of reading/skimming imagine you are going to do a presentation on that topic/subject. UNDERLINE all those words/sentences/listings whatever you think will be appropriate to be situated on the presentation slides. Keep in mind that presentations are never loaded with lots of texts. It should be maximum of 12 words in a sentence, but always try to make it smaller. In a matter of comments alongside the text, you can write the words or even small sentences regarding the topic, whatever you virtually think that will include in "presentation" Once you master this technique, you'll naturally start to annotate/underline only the necessary stuff, what can keep on track to learn/revise the topic.