Where, oh where, did I screw up?

[montybear]

Playing in a live $10 tourny, with 15 people. I am playing tight, actually beyond tight, as I've only played 3 hands in the first 2.5 hours. Each time either on the button or the CO, and everybody knows that I'm tight. The three hands that I played, I raised PF and then took down the hands either on the flop or turn, bringing my stack up to ~$25. Most everyone else is seeing atleast 2/3 flops, and there is bluffing everywhere, but the PF raises aren;t that big.
Six left out of eight at our table, I'm UTG and the villain is SB with about the same stack as me. My read on him is that he's no maniac, and plays pretty straight. Blinds are 0.50/$1.
I'm dealt 7 /images/graemlins/diamond.gif8 /images/graemlins/diamond.gif and decide to call, just to mix things up a bit. even the drunk guys at the table realize that I'm finally playing a hand and won't even limp in with me. SB raises to $2.5 and all folded to me. My read says med. pair or high ace. I call, hoping to break him, with position.
Flop A /images/graemlins/diamond.gif3 /images/graemlins/diamond.gif5 /images/graemlins/heart.gif
He bets out $2. I call (first mistake? I think he wanted to end it there)
turn 6 /images/graemlins/club.gif
He checks. I check (this is where I think I screwed up, but I thought 'hey, a free card with 14 outs, great', assuming my initial read was correct)
river 7 /images/graemlins/spade.gif
he checks and I can almost see his AK, so I figure that my only chance for the pot is to bet.
I bet $5 (too small, too big?)
Results in white
<font color="white">
villain A /images/graemlins/heart.gifK /images/graemlins/club.gif(pair A's King kicker)
me pair of sevens and lots of second guessing
he calls and takes down the $21 pot </font>

[MLG]

If you know you're beat, and you know he's too bad to fold, then don't bluff the river. Sometimes a successful hand means losing as little as possible.

[dogmeat]

Where did you screw up?

1) You played only 3 hands in 2.5 hours
2) You say even the drunks know you are a total tight rock but you call a raise thinking you will "break him with position."
3) You posted here when you already should know #1 and #2

Dogmeat /images/graemlins/spade.gif

[montybear]

I was hoping for something a little more helpful like...

1/2 pot bet on the turn when you still have outs rather than same bet on the river with the only out being him folding
and then maybe a reason or two about why that makes sense.

and I have no problem playing like that when the game dictates that. I was chip leader without ever having to worry about losing, what more would you want?

[mervhage]

I would have checked on the river. You missed your draw and you didn't invest too much in the pot. You have to believe with top pair, top kicker, he's gonna call your bet at the end.