Don't deface books, because a marked textbook is not the best way to memorise what is written. Definitely do not deface other people's and public library books. It is better to write out notes, and even try your own interpretation. Try and write a bit more when it is understood a little more, whilst keeping these notes economical. In fact develop a need for what is essential. Similarly, keep direct quotes down to a minimum.
Keep note taking accessible. This does not simply mean store in a place where they can be found. It means make them clear and easy to understand. At the same time notice the different styles of writing, and develop an academic style of your own.
Whilst speed reading is a useful talent to develop, it is useless if there is reduced comprehension. Speed reading involves taking in chunks of words at once - self training in this must be followed by comprehension tests. Reading academic material is not like reading a novel. Speed reading a novel may be more appropriate than speed reading an academic text; however, speed reading notes or at the first encounter of a source can be useful.
There is a rigid approach to writing (e.g essays - but see here) and a more flexible approach. In the rigid approach note down what conclusions to reach, what is wanted on the way to the conclusion and what order all these points should come. Check that one point comes after another in a logical order. In the less rigid approach these requirements are checked out but there is initial creative writing. Just write. It is like a brainstorm on paper, a "steamroller". The sorting out of points and order comes later.
If points do not follow on then linking passages are needed. Necessarily essays need illustrative examples. Check whether these examples really do support the point being made. Are they adequate? Would they be better elsewhere?
Make sure the introduction really gets the piece of writing off to a good start. Taking a leaf out of a journalist's book might be a good idea, where leading paragraphs offer almost a summary of what the story is about but launching the reader into the story. The journalist's opening paragraph, and questions for any work dealing with the world around it, will ask: what is it, where is it happening, why does it happen, who makes it happen, how does it happen and when did it or does it happen. However, essay writing is not journalism, and so do not give the whole game away. An essay should be like a story with a good ending. Inevitably there must be many drafts until satisfaction is reached.
In terms of the actual style of writing, there are some reasonable guidelines. Always try to be clear. Accuracy of expression is preferred over metaphors. Avoid using double negatives. Work is hard enough to follow than having to get one's thoughts around double negatives. One positive will do, or one negative. If a short word exists over a long word, and popular English over jargon, choose the short and the widely comprehensible. If a word can be cut out, cut it out. use English phrases over foreign ones - the days of a Latin phrase to add (what?) to a text are gone.
Marshall, L., Rowland, F. (1998), A Guide to Learning Independently, 3rd edition, Buckingham: Open University Press.