Biggest Leak Fixed?

I got help from arch_angel who reviewed a couple of my HU HH's. He spotted that I made many two/three barrel bluffs oop and almost always got called down. I think his remark hit the spot. Looking at my Poker Tracker statistics that has cost me a bunch.

Arch_Angel suggested that I try to follow a rule where I do not bet the flop oop, if I do not flop top pair or better. I played 10 games following this and some other rules and won 9 games out of 10 :). Here's the game I lost:

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Full Tilt Poker Game #3428731974: $2 + $0.15 Heads Up Sit & Go (26215244), Table 1 - 10/20 - No Limit Hold'em - 12:24:02 ET - 2007/09/01
*** HOLE CARDS ***
Dealt to Hero [Ah Ad]
xefu409 raises to 1,500, and is all in
Hero calls 1,480, and is all in
xefu409 shows [7d 5d]
Hero shows [Ah Ad]
The button is in seat #2

*** FLOP *** [8h 9s 3h]
*** TURN *** [8h 9s 3h] [7s]
*** RIVER *** [8h 9s 3h 7s] [6d]
xefu409 shows a straight, Nine high
Hero shows a pair of Aces
xefu409 wins the pot (3,000) with a straight, Nine high
Hero stands up
xefu409 stands up
*** SUMMARY ***
Total pot 3,000 | Rake 0
Board: [8h 9s 3h 7s 6d]
Seat 1: Hero (big blind) showed [Ah Ad] and lost with a pair of Aces
Seat 2: xefu409 (small blind) showed [7d 5d] and won (3,000) with a straight, Nine high
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In fact this same situation has happened to me twice during the last 20 games or so. I have AA, my opponent goes all-in with 75 and wins on the river with a straight...

BTW, current statistics:

$2: 27 won, 19 lost
$5: 3 won, 5 lost