In my opinion I played the hand too aggressive. How would you play the hand?

No reads on villain.

$0.25/$0.5 No Limit Holdem
6 players
Converted at

Stacks:
UTG ($26.82)
UTG 1 ($49.80)
CO ($50.25)
BTN ($66.55)
Hero ($59.53)
BB ($78.00)

Pre-flop: ($0.75, 6 players) Hero is SB [6h]
1 fold, UTG 1 raises to $2, 2 folds, Hero calls $1.75, 1 fold

Flop: [4c][2h] ($4.5, 2 players)
Hero checks, UTG 1 bets $3, Hero raises to $9.5, UTG 1 calls $6.5

Turn: ($23.5, 2 players)
Hero bets $18, UTG 1 goes all-in $38.3, Hero calls $20.3

River: ($100.1, 2 players)

I think without a read you should bet putting your opponent on:
1) Big overcards like AK/AQ
2) A decent sized pp say TT+

Okay so you check raise the flop and get called. At this point , at 50NL, I think it is WAY more likely he has a big pp than some AK hand.

If he does have AK he's probably not going to bet you off the hand.

So firing on the turn doesn't help you.

Personally, I prefer leading full potish into him on the flop. Many guys just fold the AK there.