I'm playing like a weak donky wimp from hell.

Can someone please set me straight in this hand and walk me through the errors!

Full Tilt Poker
No Limit Holdem Ring game
Blinds: $0.50/$1
4 players


Pre-flop: (4 players) Hero is UTG with
Hero raises to $4, Button calls, 2 folds.

Flop: ($9.5, 2 players)
Hero bets $6, Button calls.

Turn: ($21.5, 2 players)
Hero checks, Button bets $15, Hero calls.

River: ($51.5, 2 players)
Hero checks, Button bets $35, Hero calls.

Results:
Final pot: $121.5

Preflop: This is fine

Flop: I would bet a bit more, say $8 - $9

Turn: Ick, I don't like this check. When he bets, you have no way to tell if he's betting because he senses weakness or because he has a better hand than you. I prefer leading out for about $15 and seeing what he does. If he raises you can throw the hand away - there's just too much you lose too and too little you beat. If he calls, you're probably good but want to play the river cautiously. He could have An ace himself (AT, Ax) or even a queen (KQ, QT) as well as a spade draw. Of course he could also have AQ, AJ and KT which you are now behind to.

River: Assuming he calls your turn bet, the pot will be about $50. I'd bet about $20 as a blocking bet, folding to a raise. Another line you can take is to check and call a decent sized bet assuming he's betting to rep the flush or something with complete air, but I prefer to leave those for situations where the flush didn't make it and he's betting a missed draw.

I think that if you check the turn and he bets relatively strong, you're better off folding.

Position, reverse implied odds, possibly drawing dead... everything is working against you here. Yeah you have a decent hand but I think you're much better off folding the turn in the long run.

If he flat called the flop with AJ, AQ or KT, which is reasonable, he has you crushed. You can not beat much more than a bluff here and with two more streets and being OOP on a super drawy board I don't think you should be trying to catch him. Give him credit for having position and fold... unless he's a habitual floater/bluffer, in which case you should push.