I guess this is mainly derived from live play (where one isn't working with tracking software for one thing) but should also have some merit for online.

What I'm interested in here is what the most important things are to look for--i.e., after a few orbits you should have at least some definite hypotheses on all of these.

So, here's my list:

1) What's the right raising quantity for the table? This is quite variable depending on tables. I'm generally looking to get 2 callers, although many good players like only 1 (and hence like to raise bigger).

2) What are the raising ranges of your opponents? I think this is probably the most important thing to figure out pretty quickly. Against some it is a huge mistake to lay down AQ to a raise (I'm talking about FR here by the way) because they're dominated more often than not. But against a few (definitely the minority in my game), it's a fairly big mistake to call a raise with AQ because YOU'RE dominated more often than not.

Depending on raising ranges, I also make major variations in my re-raise range: Against very tight raisers, my re-raise range is AA only. Against very loose ones, it's at least JJ+ and AK and usually with a healthy dose of SCs and middle PPs in the mix.

As 2a one might also add how they'll respond to a re-raise. There are some at my 1/2 who'll shove AJ or worse, but most will let the re-raiser have the initiative unless they have a really big hand.

3) What do they bet, and are there any betting tells? I was noticing tonight that several players would bet near pot on second pair, then check turn without improvement. Many will also semi-bluff with a half-pottish bet. Lots will check top set after raising. One player I was noticing bet double the (limped) pot with TP no kicker on a mildly drawy board, and that's a fairly frequent play actually--but some do that on 2 pair a lot, so you need to know your player.

4) Weak means strong players. Some will shrug or give a weakness comment when they bet on sets or other nut hands.

Those are the main ones I can think of right now. Certainly point 3) is a large area which could stand to a lot more differentiation.

I also wish I had some better physical tells to share. Honestly, my current status on that is that I feel like I have a pretty good sense of whether I'm ahead or behind or whether someone has a big hand or not, but I feel like I still have a way to go in that area.

Oh, and another one I wanted to mention that I just remembered:

5) Who is bluffable and who isn't? Basically, this amounts to who is capable of laying down draws or TP. Against these guys, I've often been semi-bluffing the turn at around full pot if I've been able to isolate and if I think they're drawing--or often repping a set by 2/3-potting if I think they probably have TP. Other plays are obviously also possible. Against stations obviously on a draw, I've also been full potting the turn (sometimes overbetting) on overpairs, TP I know is good and stuff like that.

Your list is great !

I just miss an important point : The likeness of someone playing on tilt, drugs, alcohol ...

I usually sit out if no one straddles.