I sometimes overthink situations when I'm trying to put somebody on a hand. I never put somebody on one specific hand; I try to put them on a range of hands with some being more likely than others simply by the odds of them being dealt, and some being more likely because of previous betting patterns from that player I've seen. Then I decide if I'm probably ahead or probably behind, look at the pot odds, and take it from there....unless I'm getting tired/bored, and then I just go with my instincts

Here's an example:

3 people see the flop in an unraised pot. I've got Q9o in the BB. Flop comes:

Q T 3 rainbow.

I check, next player checks, last guy fires out a near pot sized bet.

My read on this player:
Semi-loose, hasn't been caught bluffing/semi-bluffing, will bet 2nd pair if checked to him.

So his range of hands that are ahead of me post-flop could be:
AQ (8 different ways of being dealt), but I discount 50% from this since I think he would have raised AQ pre-flop for a score of 4.
KQ (8 different ways)
QJ (8 different ways)
33 (3 different ways)
QT (6 different ways)

There's other possibilities, but these are the most likely hands he could have that beat me since it's an unraised pot. Total score = 29.

Now, for the hands that he might bet that I'm ahead of:

AT (12 ways)
KT (12 ways)
JT (12 ways)
T9s (2-3 ways)

Total score = 39.

He could be bluffing or have limped in with a monster, but I figure those are unlikely enough that they cancel out. Largely based on the fact that I believe that my opponent will bet 2nd pair in this situation, I decide that I'm most likely ahead at this point and either call/raise.

Are you going to do all that math in your head in 10 seconds? No. You'd be suprised though how good you get at doing a rough estimate of what's most likely, to the point that it becomes like instinct.

The point of all this jibber-jabber is don't put your opponent on one specific hand. Just decide if what they have is probably better or probably worse than what you have. If you're probably behind, ask if pot odds justify a call.

Sorry if I made this wayyy more complex than it needed to be