Personally I avert taking notes in the book itself, but I do use sticky-notes for future reference.

The types of notes are dependant on the type of research I am conducting. I will not make a note on the '1990's Automobile Production' in a certain book when I am researching 'The Ecological Effects of Medicine in the 1990's' from the same book. The example subjects might both have the 'evidence' I am looking for but not all of it is ressourcful.

Non-research related notes, and thus more studious ones, differ depending on the subject, but generally share the same format. So say I am studying 'Ireland from 1730-1930,' then I will focus on the chronology of events as my format. That means the title font on my first page, along with page number(!!), will have a title such as '1730-1750: Subtitle'(usually the prof/book will have a subtitle for their seminar/chapter). The proceeding notes will be classified by the profs/books and their slides/paragraphs. I like to use lines and triangles to classify the topics and subtopics, which ends up creating blocky and linear notes.

I try to be careful not to transcribe the profs/books notes too literally though. I try write it in my own way, and to even add my own questions into the notes, and to not just copy the slides(if there are any) or a word for word replication of the paragraph(unless of course I am quoting it directly). This teaches me to stay objective of what I am reading and to practice thought experiments, for no history book, incculding my own(!!), is unbiased!

What about you?

Edit: Some grammar and such. P.s. depending on your prof you might want to be more literal in your copying. Profs are sometimes very peculiar with their terminology and their grading, I can spot these a mile away.

I type my notes, and back them up to the cloud every few minutes using a macro.

Each source gets its own page, and I start with a standard bibliographic entry and a call number. I usually start by perusing the index for relevant entries, or by browsing a chapter that I think will be appropriate.

Each entry is a page number, followed by a keyword or category that I would assign to it. Then I make my note. I type out a fair amount of detail, but not so much that I am just copying the whole page - if I later decide that I need more detail, I can always go back to the source. I sometimes paraphrase, but I also record direct quotes that I'll paraphrase later. I feel that this keeps my writing closer to the original author's meaning, but maybe you don't need to do this as much. I guess what I am saying is that I want to be careful about rephrasing my own paraphrasing lest it diverge too much from the original text.

If you read several books about the same topic, you might find that the authors are sometimes using the same source material, and stating similar ideas. Rather than repeat facts over and over, I try looking for themes in their writing, or anything that gives me a "Eureka" moment since I feel that those things will make my writing really stand out. These are the sort of details that will make you excel if you need to discuss the book in a seminar or other discussion.

I'll typically work this way in a library, grabbing one book at a time, and returning it to the bin when I'm done. Eventually, I end up with a fairly lengthy Word document that I print off and read over, highlighting especially useful points. Sometimes I'm able to copy and paste directly from my notes into an essay, which saves time.

Journal articles are different. I'll usually peruse them online, and if I feel they are useful, I'll print them off and make my notes right in the article. However, I would say that most people I know do not bother printing them, preferring to read them on their computer.