If you have a tight playing style then big pots are the ones you want to watch carefully, as these are the pots you want to play in. Looser styles move towards trying to pick up smaller pots, and for this reason you want to focus on the smaller pots that are shown down. Obviously knowing somebody only calls a flop bet with TP or better can allow you to make more stabs.

At low stakes it is easy enough to use broad categories for opponents and you can very likely profit from playing against them based on what you know of this category from prior experience. Notes will probably not help a great deal as it's unlikely you'll get enough hands in with a given opponent to make good use of them, and over the small sample size you have, could be inaccurate due to the players mindset at the time.

If you multi table you may open one table at a time, paying attention to the players for two orbits or however long until you feel there is enough information on offer.

If while playing a new player joins your table, you may be able to gain information immediately by the amount they buy in with and whether they post their blind OOP. Although this doesn't give you an indication of what cards they will play, I believe that a short stack posting their blind in the CO is more apt to play their hands badly.

Try to get an idea of what players at your table are aware of their position. This is one of the easier things to spot and should give you an indication of their overall knowledge of the game. By coupling this with an idea of their playing style you will, with experience, be more able to pick the correct spots to play with this player. Remember that not all opponents will give you the implied odds to hit sets.