How to take notes while reading textbook?
I tend to have problems documenting-while-reading as well. What tends to work for me is either:


Read all of the resources on your topic that you find, and then write a summary of what you've learned immediately afterward. Try to have enough detail that someone following behind you can make sense of what you write. (In a few days, you will be that someone!)
If I have a specific need (say, to defend a point I'm trying to make), then I'll quickly jot down bullet points while I research, but no more than that. Then when I'm finished with my research, write the summary described above.