It's very important to organize what you're learning. You can't learn from different sources without any concept and let everything mix up and repeat. Also, you can't learn unimportant informations. You need to summarize notes and text from book, to make your own summary and study from it. Have problem with doing that? Here's help!
Highlight keywords/ages from your notes and from book. It can be better if you use different colors for different type of keywords. First thing my teachers aks is 'what is (keyword)?' If you want to learn as little as possible, you should know definitons for all keywords but not any more details for less-important ones.
Write them on paper or in notebook and write their meaning. Don't repeat them. Write them in order of their types (colors).
Connect keywords with a story. Write story by reading comparatively your notes and text from book. Make sure you understend it and that you have all informations you heard in school (from your notes).
Find specific order. Write in chronological order or any other that make sense and helps you learn and understand easier.