Is this the proper way to milk someone with a set?

BTW Here's my concern with this hand.

Did I bet too softly? No real reads here. I just sat down minute ago. PokerNOW players seem to be really tight, so I have had to tread lightly with my big hands (always afraid their gonna fold).

I put this guy on a big hand like Queens or Kings. Given that, should I have bet more than I did on each street (1/2 pot)?

UMM

Something weird happened and my last post (of the ACTUAL HAND) didn't get posted.

So here it is.

Party Poker No-Limit Hold'em, $ BB (9 handed) FTR converter on zerodivide.cx

Button ($18.20)
Hero ($28.73)
BB ($50.85)
UTG ($34.40)
UTG+1 ($22.65)
MP1 ($28.15)
MP2 ($61.34)
MP3 ($41.55)
CO ($29)

Preflop: Hero is SB with 4, 4. Hero posts a blind of $0.10.
UTG calls $0.25, UTG+1 calls $0.25, 1 fold, MP2 raises to $0.5, 3 folds, Hero (poster) calls $0.40, 1 fold, UTG calls $0.25, UTG+1 calls $0.25.

Flop: ($2.25) 5, 4, 9 (4 players)
Hero checks, UTG bets $0.25, UTG+1 folds, MP2 raises to $1, Hero raises to $2.5, UTG folds, MP2 calls $1.50.

Turn: ($7.50) 8 (2 players)
Hero bets $4, MP2 calls $4.

River: ($15.50) 3 (2 players)
Hero bets $7, MP2 calls $7.

Final Pot: $29.50