I'm bored whilst playing so I thought I'd rail you and see how you're doing. Here's one example of a hand I feel you misplayed.
PokerStars Game #63032674617: Tournament #424010421, $5.00+$0.50 USD Hold'em No Limit - Level XIV (800/1600) - 2011/06/06 21:44:02 WET [2011/06/06 16:44:02 ET]
Table '424010421 119' 9-max Seat #4 is the button
Seat 1: Cr@cker717 (84857 in chips)
Seat 2: pestaras85 (25701 in chips)
Seat 3: Vindel (68378 in chips)
Seat 4: getaraise (42875 in chips)
Seat 5: stilli rom (16623 in chips)
Seat 6: Lehmo81 (64862 in chips)
Seat 7: jam3s1nlove (56311 in chips)
Seat 8: Ironside (60055 in chips)
Seat 9: PokerCity00 (31866 in chips)
Cr@cker717: posts the ante 150
pestaras85: posts the ante 150
Vindel: posts the ante 150
getaraise: posts the ante 150
stilli rom: posts the ante 150
Lehmo81: posts the ante 150
jam3s1nlove: posts the ante 150
Ironside: posts the ante 150
PokerCity00: posts the ante 150
stilli rom: posts small blind 800
Lehmo81: posts big blind 1600
*** HOLE CARDS ***
jam3s1nlove: folds
Ironside: raises 1600 to 3200
PokerCity00: folds
Cr@cker717: folds
pestaras85: folds
Vindel: raises 3200 to 6400
getaraise: folds
stilli rom: folds
Lehmo81: folds
Ironside: calls 3200
*** FLOP *** [

]
Ironside: checks
Vindel: checks
*** TURN *** [

] [

]
Ironside: bets 9600
Vindel: calls 9600
*** RIVER *** [

] [

]
Ironside: checks
Vindel: checks
*** SHOW DOWN ***
Ironside: shows [Ah

] (two pair, Aces and Sevens)
Vindel: mucks hand
Ironside collected 35750 from pot
*** SUMMARY ***
Total pot 35750 | Rake 0
Board [

]
Seat 1: Cr@cker717 folded before Flop (didn't bet)
Seat 2: pestaras85 folded before Flop (didn't bet)
Seat 3: Vindel mucked
Seat 4: getaraise (button) folded before Flop (didn't bet)
Seat 5: stilli rom (small blind) folded before Flop
Seat 6: Lehmo81 (big blind) folded before Flop
Seat 7: jam3s1nlove folded before Flop (didn't bet)
Seat 8: Ironside showed [Ah

] and won (35750) with two pair, Aces and Sevens
Seat 9: PokerCity00 folded before Flop (didn't bet)
Fold pre for a starters or fold to the 3 bet.
As it is, I like the check on the flop and the lead on the turn, but you should always be betting the river. You've no reason to fear the flush given how passively he's played it and on the river he's checking back nearly always given he's flatted your turn bet. He's often got a hand like QQ that's checking back as he wants to get to showdown as cheaply as possible in the hope you've bluffed the turn.
You can also get him to fold and don't have to go to a showdown...and given you've called a 3bet OOP with a7s that's no bad thing.
I'd suggest you get a decent player you respect to ghost you during a session so he can see where you're missing out on value bets etc.