IMO - Most freerolls are a total waste of your time for the following reasons:
1. Typically there's no prize money to speak of e.g. Full Tilt $100 freeroll pays $15 top prize and will take approx 3-4 hours of playing.
2. The Kudos of cashing even top 3 in a freeroll is very short lived because a) the prize is so pathetic and b) it means jack because freerolls are not "real" tournaments.
So what possible reason can there be for playing them at all unless they have a big payout.
Far better to stake $10 on a low limit cash table and play tight poker and you'll easily make $10 in about 30 mins.
There are some good freerolls though. For example FT has a newbie freeroll each month and it's awesome. For all people who joined FT this month they get entry into a private freeroll with $10,000 prize money. Obviously if you know how to play poker you will definitely cash because most of the opposition are newbie donkeys. Most of those won't even realise they have entry and will not turn up !! Unfortunately this freeroll wasn't available when I signed up last year
Strategy wise for these decent freerolls you just have to bide your time and play tight aggressive (which is dreadfully boring of course) and make good pots from your good
hands. Slowplaying monsters like AA and KK can work very well but can be very risky if there are 3-4 people seeing the flop. On the approach to the bubble you MUST forget about cashing and play as if there was only a 1st place prize. There's nothing worse than sitting back and being passive and just hoping everyone else will fight it out and knock themselves out thereby moving you up. It's a terrible strategy. Play to win or not at all. Get your chips in strong when you have a good hand no messing, no worrying that you might drop out at the last minute, get them in. If you get sucked-out tough luck. Try again next time.
Limping across the line is a failure and you should see it as such. In a "real" tournament with a cash buy-in you can not sustain a profit by just limping over the line, it just doesn't pay enough and you don't get across the line often enough for that to make money. It's a losing proposition.
So, my view is, well before you get to an M of 10 and have to start worrying about making a move, make a move. So with M of 12-16 start making moves. Raise all-in on the button to steal the blinds or do whatever you need to. Make the move early not later when you have M<10 and everyone knows why you are making the move and calls you.
Play to win outright, that's the key.
Good luck