That's an excellent question.
One starting point is the Nash equilibrium. It is good for players who are new to SNGs to spend some time with PokerStrategy's ICM Trainer.
You should also draw from your memories of hands. You can try to tell whether a hand was at the edge of your opponent's calling range from timing tells, too. A quick call usually means your opponent did not think it was a marginal call, while a slow call could mean it was close to the edge. After a while you should get a feel for what hands you would find surprising to see when you are called. Of course, some players are looser and some are tighter. You may want to stereotype your opponents, e.g., as a loose-passive casual player, or a tight-early reg, and estimate a different calling range for each stereotype.
Once danger of using your experience is that you might put people on ranges which are too wide since you see if your opponents make a loose call with JT, but you don't get to see if an opponent makes a tight fold with AQ.
You can look into your database to see how often your raises are called from each position and each effective stack depth. You should try to avoid mixing together hands where you make a small raise with ones where you pushed. In HEM, you can look at the steal success rate from the SB, BTN, and CO, in the report by the number of players, and filter to a particular effective stack depth.