Value and Range

As a start point for considering pot odds, a opponents range is important. Are they pushing a short stack from late position? (ie wide range) or are the so tight that a reraise could only really mean a high pair pre-flop or a hand like two-pair or a set post-flop?

Alongside range you should consider value. How much is in the pot in relation to the cost of the call?

And then alongside both of those your should consider odds of drawing against the range.

Lets give an example. There is 3000 in the pot, and villain launches all-in for approx the pot size, and action is folded to you.

The call cost is 33% (ie call 3000 with a view to winning a 9000 pot). You would need to be drawing better than 33% EV against the majority of villains range.

If you realistically but him on a range of say 5 possible hands and your EV's against those hands are:
18%
40%
49%
22%
35%
then there is enough value in calling. The EV (Expected Value) is ahead of the call cost in the majority of hands in his range, therefore call.

The more you go back and analyse your crucial hands in detail, the more you will gradually plug some leaks, and develop a more accurate understanding of value in various scenarios