I lose way more sets than I win, so each loss comes right here. There has to be a way to play these better, so I can win, either that or I'm just _extremely_ unlucky.

PokerStars No-Limit Hold'em, $0.10 BB (9 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

UTG ($9.55)
UTG+1 ($10.50)
MP1 ($3.65)
MP2 ($10.40)
Hero ($6.55)
CO ($2.05)
Button ($9.85)
SB ($10.30)
BB ($14.55)

Preflop: Hero is MP3 with 5, 5.
3 folds, MP2 calls $0.10, Hero calls $0.10, 1 fold, Button calls $0.10, 1 fold, BB checks.

Flop: ($0.45) 5, Q, K (4 players)
BB bets $0.3, MP2 folds, Hero raises to $1.2, Button folds, BB calls $0.90.

Turn: ($2.85) 3 (2 players)
BB checks, Hero bets $1.5, BB calls $1.50.

River: ($5.85) 4 (2 players)
BB checks, Hero bets $2.5, BB calls $2.50.

Final Pot: $10.85

Results in white below:
BB has 6c 3c (flush, king high).
Hero has 5d 5h (three of a kind, fives).
Outcome: BB wins $10.85.

I was planning to just check the river with the club hitting, but with him checking ahead of me, I figured he didn't have the flush.