And how ?
Simple question !
I have to say I don't, I keep my books immaculate, like if nobody had read them, I don't know if it's strange, because I feel that when you annotate a book, you bring him a part of your personality, the book become really specific to you, it become yours.
Despite this, I'm still unable to do it !
Sonya Kar, It is exactly what I feel and I have a similar method
I write all the notes in a notebook or on Word and save it.
Despite that (the deecration), and bizarely, I think sometimes that annotatong can be something great, like in these David Foster Wallace anootated books :
http://www.hrc.utexas.edu/press/releases/2010/dfw/books/
For a long time, I used post-its with every book I read, stuck on the back cover, and the method was simple : everytime I find an unknown word I write it on the post it, if it was a sentence, I just take the page number for reviewing.
Now, I don't use post-its (it was a little bit cumbersome), I make a mark next to a sentence or a chapter, but I only use my small IKEA pencil.
I don't either, and felt it was strange too, as my writer friend's tend to write all over theirs. I simply can't. A beautifully bound book, with pristine pages is a pleasure to hold and I think of personal scribbling as some form of desecration.
I keep notes though in a separate notebook - invariably I will spend an hour reviewing and scribbling notes from a book I loved into one notebook, now 7 years old, which is a pleasure to browse through in my spare moments.
Hmmm..... I usually don't use my books for writing, but sometimes I love to do so as it keeps me related with the chapter or topic.