IMO the best way to take notes is to keep it simple. Find your own shorthand because you don't have time to read a paragraph when you're trying to make a decision. I will usually break mine down by streets with any extremely pertinent information at the top.
!!!Huge Fish, Calls ANY AIPF With ATC!!!
PF: OLimp/Call AA @MP w/3; Comp any SB;
F: Ch/R = Set+; Floats all bets w/ Str|Fls
T: F if float didn't make it
R: Showing down anything if made it this far.
Just off the top of my head, pretty extreme fish example. Usually as I play someone more I will modify/simplify if two notes are similar(QQ+ instead of two similar with AA and QQ etc)
I color code just off of my HEM stats just to help me notice quick at the table or when I am going through the lobby.
You don't need to be extremely specific, sometimes I will just write TP instead of QQ.
Going back to what I said earlier is probably the easiest way to help yourself take more notes: keep it simple. If you feel like every time you're taking notes you're writing a novel, then you won't want to, nor do you have the time. But when you're only writing 10-20 characters, it's much easier. One way to make it faster at first is to always keep this copied to your clipboard, so you don't have to keep writing this same thing over:
It saves seconds, but they add up when you're taking a bunch of notes.