How to Improve endgame strategy.

[mjm]

I am getting crushed at the endgame.

Stats for May:
Played 821 SNG's (mix between Stars $27 turbo's and $22 regulars)
Finish distribution:
ITM: 40.07%
1st:96
2nd:139
3rd:99

Probably a lot more 4th's than any of these.

I am winning chips at every level upto 100/200 blinds. Then, a marginal loser at 100/200, losing 0.02 bb/hand at 200/400 and 0.5 bb/hand at 300/600.

These stat's show a massive leak in my game, right? (I know small sample size, but assume this is my long term norm)

So what is the best way for me to go about fixing this?