Having trouble with hand selection late in tourneys.

I have been playing cash games seriously for about 6 months and I have about 2 years of total experience. Never tried out MTT until this week and I'm doing VERY well.

Played a total of about 5 tourneys, most are $24+2 on FullTilt.. stuff like $18k or $28k Guarantees with about 700-1100 players.

I've played in top 50 3 times and top 150 the other 2. My best finish was 15 so far...

I'm having trouble late in tourneys choosing hands and making good plays when it gets down to ~30 people or so. I can be chipleader, dont know when to call with medium ace etc etc... I know almost any PP is good in late play but still.

For example, ~40 people left and I have this hand in MP with 4th in chips, what to do? I'm 4th in chips yea, but what if I miss, thats a big chunk of chips!

Not sure why its not putting all of it, but blinds are $1000/2000 and the raise was to $7400. But the same guy has been doing it for a while to $7400

Full Tilt Poker (9 handed) Hand History converter Courtesy of PokerZion.com

Preflop: Hero is MP1 with Q, K.
UTG raises, 8 folds.

Final Pot:

Results in white below:
No showdown. UTG wins .

what are stacks in this example? If he is 3 betting light utg, then jam... late in mtt's you have to adjust to your table. If the table is tight, than open a lot. If your table is aggressive, pick off weak openings with 3-bet shoves. It really depends on stack sizes. I tend to pick on medium stacks that can do nothing but play nitty. I only really open light with 25+bb's; with 15-24bb's, i pick a player that is loose and weak, and shove whenever he opens. Just pick your spots well and don't be afraid to stick it in if you feel its right. GL!

How big are effective stacks?

Really, there aren't any realistic stack sizes that would make me want to do anything but fold to a 4x UTG raise, but I felt like asking anyway.