Looking for suggestions for improvement on A/Q hand, KQ3 flop

[LearningCurve]

Early to table and so far villain had been very loose but not obviously agressive. Basically looking for suggestions to avoid feeling dopey at the end of the hand.

Poker Stars
No Limit Holdem Ring game
Blinds: $0.05/$0.10
8 players
Converter

Pre-flop: (8 players) Hero is BB with Q[img]/images/graemlins/spade.gif[/img] A[img]/images/graemlins/heart.gif[/img]
UTG folds, UTG+1 calls, MP1 folds, MP2 calls, CO calls, Button calls, SB calls, <font color="#cc0000">Hero raises to $0.4</font>, UTG+1 folds, MP2 calls, CO folds, Button calls, SB folds.

Flop: K[img]/images/graemlins/heart.gif[/img] 3[img]/images/graemlins/diamond.gif[/img] Q[img]/images/graemlins/heart.gif[/img] ($1.5, 3 players)
<font color="#cc0000">Hero bets $0.5</font>, <font color="#cc0000">MP2 raises to $1</font>, Button folds, Hero calls.

Turn: 6[img]/images/graemlins/spade.gif[/img] ($3.5, 2 players)
Hero checks, <font color="#cc0000">MP2 is all-in $3.8</font>, Hero folds.
Uncalled bets: $3.8 returned to MP2.

Results:
Final pot: $3.5