When you sit down at a table where every player is an unknown how do you learn how they play? Do you have a system like just focus on one or two players at first? Or do you just actively pay attention to every hand and metabolize the information as it comes in?

I get a little overwhelmed trying to pick up too much at once.

If you are talking about a friendly social game, you will usually see the same folks more or less session after session. Stuff about them and their styles will be fairly clear after a few game nights. Some underground raked rooms also have a lot of the same folks session after session. Casino tables have a faster turnover and often different players each session. Much tougher , almost impossible, to deal with everybody effectively. Personally I try to find the most aggressive players (because they stand out) and try to deal with them mostly.

Play tight and observe. That sounds easier than it is.

You'll have a solid guess about preflop looseness after one rotation. Aggression reads will take longer unless you are sitting with a maniac.

Post flop reads are going to take longer, especially vs a tight player. You may not get a read on post flop play fast enough - i.e. before the villain gets up and leaves the table.

I pay special attention to players who fold their small blinds in a limped pot. That can be a sign of skill.

I do not recommend focusing on a couple of players to the exclusion of the rest of the table. More so if this is a traditional casino setting where the players change all the time.

DrStrange

Def the bolded. Just relax, play tight, and pay attention to everything. I cannot stress this enough. That's the major flaw that most people have, they do not pay enough attention at the table.

Try taking it in little steps. Pay close attention as mentioned above. After one orbit or so, just simply try to classify each opponent as either tight or loose. Nothing else. After another orbit, see if you can put a passive or aggressive label on each person. With practice it will come easier. Taking it in small steps can help you feel like you're accomplishing something which in turn can make it less overwhelming.

All helpful so far. Thanks

Once you get a solid read on a particular opponent, you can then adjust your play as necessary.

The most important aspect of reading people is the stakes and level that you are playing. Generally, if you are at 1/2 or lower, then you basically get what you see. At 2/5 and higher, you start to see people that are aware. This means two things. One, it is very possible that they are going to send you reads that are not accurate. Two, if you aren't aware of your own image, they will be able to read you and play more optimally against you.

In the home games in which I have participated, some opponents are more aware than others, regardless of the stakes. But even my dense opponents, at least some of the time, will try to mislead me.

Buzz

Aggressive opponents are like the weeds that grow taller than the rest. They always get cut down first.

As Dr. Strange noted above - Preflop reads are the easiest to accumulate at the initial stage simply because you will gather up a decent sample size on your observations pretty quickly. After 2-3 rotations I am usually able to gather some pretty good info on player tendencies based on PF play
Players who limp/call a lot - Loose/Passive Preflop
Anyone who limp/calls a 3-bet (or more) when stack sizes aren't deep enough gets a loose PF label until proven otherwise.
Anyone who seems to flat out of position routinely - probably not positionally aware

Postflop you can also gather some pretty good info fairly quickly even without seeing a showdown, usually this pertains to bad play.
Players are normally bad if they:
Make same size bets on multiple streets/seem to bet size in absolute terms
Bet size awkwardly (example: overbet flop and then bet 1/4 pot on the turn)
Check/Call large bets on early streets just to fold the river when they have a small % of their stack left (i.e. clearly chasing without the odds passively and folding river when they miss)
There are also cases where a single hand that reached showdown can provide some information, for example:
Show someone is capable of 3-betting/4-betting light preflop
Show someone does NOT 3-bet/4-bet (or even raise) with some premium hands (like KK, QQ, AK, etc.)
Show someone is capable of 3-barrel bluffs
Show someone is capable of semi-bluffing on early streets with a draw

This is most certainly not true.

I'm not talking about getting stacked, but that they are weeds that grow faster than any others. You notice them first. You don't notice the people not in the hand.

That's fine for the first half of your statement, what about the second?

Try this Concept of the Month in LLSNL.