MK over at the Taking Note Blog just commented on my recent post about one thought per note. He helpfully adds several more links on the same idea and mentions that this is “one of the most basic features” of his note-taking.
I have mentioned the Taking Note Blog before, and I highly recommend it. A few years ago I took a saturday and read through every single post in the archives—and have kept up with every post since. This has probably been the single greatest influence on the way that I think about managing information. So head over there and start taking notes!