hi Jeffers
I find it depends from site to site - some are easier to make quick notes at (I really like carbon for this) and others are better to work on a colour code system (eg. pokerroom or fulltilt)
I try to keep some method but its very flexible - I generally try to note a general style if they are consistent and unable to change gears
I also have a very simple "watch" note - this may begin to tie in with addition notes - but it just gives me a signal to watch out for them - either because I think there is more to their play / they were a bit tricky or that they were a bit random - but not an instant donk note player
also if I see certain key type hands (eg. AA, KK, KA, 88 or mid pairs, Ace rag, low pairs, QQ / JJ /10 10) played in certain ways I can either take advantage of or avoid then these are really handy
if you have notes like - consistent 4x BB raise or re-raise any position on big PP a-10 that tells you alot when you come back to a game
also you migh find some of our article on making notes useful ...
Win More Making Poker Player Notes
cheers scrawnybob
ps. I think any notes are useful and worth doing whatever you can - if you put it in an order of importance even better
I keep the first line for a general description / judgement on the player - eg. Shark, Muppet, Loose Aggressive, Tight ABC, Passive, Tricky or WATCH
then add hand notes below for detail