I've never been particularly good at note-taking, but I'm very aware of it's positive effects. One thing I intend to do going forward is to ensure that whenever I read an article of value (i.e. something that ends up on my Pinboard account), that I take some notes as a reflection of what I learnt from reading that article.
Another trick is to “keep it short”1. Write more often, but write less and try to emphasise clarity.