I have played over 15k hands on microstakes now and i analyzed my hands to see where i should improve. I noticed i lost lots of hand when i had top pair but vilian had 2 pair.
I find it really hard to know when someone has 2p. The problem is that i see lots of people do the same thing with pocket pairs, even if there is an overcard on table.

For example this hand: i played it yesterday

Poker Stars, $0.05/$0.10 NL Hold'em Cash Game, 6 Players
LeggoPoker.com - Hand History Converter

SB: $9.55
BB: $23.45
UTG: $5.50
MP: $12.20
CO: $19.35
Hero (BTN): $9.85

Pre-Flop: K J dealt to Hero (BTN)
2 folds, CO calls $0.10, Hero calls $0.10, SB folds, BB checks

Flop: ($0.35) 5 J T (3 Players)
BB checks, CO bets $0.25, Hero raises to $0.70, BB folds, CO raises to $2, Hero calls $1.30

Turn: ($4.35) A (2 Players)
CO bets $2.50, Hero calls $2.50

River: ($9.35) 2 (2 Players)
CO bets $4.75, Hero calls $4.75

Results: $18.85 Pot ($0.90 Rake)
CO showed T J (two pair, Jacks and Tens)

did i play this well or should i have raised this hand because i had the button?
Should i fold on his reraise? The guy was playing aggressive and was 30/20/12
so i really didn't know what he had... few hands before i've seen him playing the same action when he had 88 on a flop of A73.

Once he 3bets the flop, you only beat KQ and QJ, probably fold after the 3bet, but I dunno if I would raise the flop as we don't get called by too much that we beat.

I would generally raise preflop to isolate the CO.

This is your biggest mistake, you're on the button with a decent hand, raise it up like a man!

I like your call on the flop given his AF of 12 but turn should be a fold, straight draw hit and villain doesn't seem to be scared of the ace...

Definitely raise it up preflop. You really want to own people on the button -- raise it a lot, especially facing limpers.

His flop line is pretty strong. A flop 3-bet will usually mean he has top pair good kicker beat.

I raise it preflop, and I fold to his 3-bet on the flop.