(Disclaimer: This is info I've gained from personal observation. I did not conduct any statistical studies or wade through tens of thousands of hand histories. And, as always, there are no "always" rules in poker.)
As someone who plays SNGs and MTTs almost exclusively, I feel one of the worst things to run into is a set. I used to routinely stack off to them with big overpairs or top pair/top kicker. It sucks in a cash game but it's obviously devastating in any kind of tournament.
Over time (especially the last 2 years) I've noticed certain clues that, to me at least, make a lot of sense in terms of poker playing and human nature.
Simply put, when someone has a huge hand they generally want to make as much as possible off of it. When someone has a hand that is perhaps marginal, but offers outs, they generally would prefer to win it right now, getting a smaller reward by driving their opponent away.
These betting patterns are only fairly reliable (say 80% plus) when it's early in a tournament and stacks are deep.
Overall, I've found these betting patterns most significant when they come in the form of a checkraise.
Sets: I raise from any position with AA and am called by one of the blinds. The flop comes "safe" with rainbow rags. The player first to act checks and I c-bet 3/4 of the pot, only to be checkraised the minimum or, depending on stack sizes, the pot. To me, this is a set. Granted, depending on my player reads/notes (if I have any early on) I may call. And depending on the size of the raise I may still call, but always with the thought in mind that I'm likely behind. Still, my first thought is "set". Do I get bluffed off hands? I'm sure I do. But I'm also sure I've dodged many a bullet.
As a side note, if we're further into the tournament and the caller's stack is fairly small, you can be assured you're dealing with a set. Anytime a shortstack is obviously "milking" you he's got a monster.
Draws: Same preflop raise and call but the flop is rags (or perhaps one facecard) but two of the rags are of the same suit, say the flop is Qs, 7h, 4h. I cbet my AA and am checkraised allin. Now I suspect a draw, most likely a flushdraw. Online, at the lower levels, this can be anything from AhQh to 6h5h, to JhTh. (True, it might also be AQ,KQ,QJ as some players will play these the same way.) There's no way to know obviously, but this is rarely a monster hand of any sort and I call or fold based on a different perspective.
I'll admit, none of this is guaranteed. But it works for me and I thought I'd pass it on.