The best way to take notes is to not do it during the class. Pay full attention only to the teacher/speaker during the class/lecture and make a conscious attempt to remember everything they said. Immediately following, get together with 3-5 like-minded friends and attempt to as a group write the entire lecture from start to finish from memory. If no one can remember something, skip it.

It takes a few weeks/months to develop your focus, attention span, and memory enough to be able to get near 100% short-term retention, but you start to see benefits almost immediately. And the long-term benefits to your memory and focus can't be understated.

Also, it's really interesting how many other people are expressing that they never took notes in college. I was famous for it in my college (my advisor wrote a paragraph about it in grad school recommendations), whereas I always thought it was common sense, seeing other people who spent the whole class scribbling, but didn't really understand a bit of what was actually taught.