First thing to do is to look at how much they open raise or how much they are calling raises,
This gives you a good idea about what range they are playing preflop.
Then look at their cbet/foldcbet/donkbet % and that narrows the range down more.

Whenever a hand reaches showdown, go in the hand history to find what each player had. It's a good way to start narrowing your opponent's ranges according to the actions they took (by backtracking).

If you have a HUD a good thing to do could be to look at a hand vs someone you have a decent amount of hands against in your hh and find a hand you played vs them. ( preferably one you can't remember)

Then just play through the hand using his stats and try to narrow his hand range down street by street by the time you get to the river see how often you are right or completely wrong.

example:

UTG1 opens 16% range, we call on the button

so far we assume he is opening something like 22-AA, ATs+ KTs+ AJo+ A2-A5s (use pokerstove for this)

Flop AJ4r and he checks. 

We assume he would bet his good hands here, like AQ+ and sets for value, then bet his semi-bluffs KT/KQ and check his more marginal showdown hands. So we eliminate these from his range, leaving him hands like A2-A5s, Jx and 22 - KK. 

we bet he calls.

We can now eliminate 22 - TT since he would likely just fold these, so we know almost exactly that his mostly hand is a marginal one pair now and we can play our range accordingly...

obviously when you start playing BB vs button ranges it becomes tougher since there are a lot more hands to think about etc. Hope this helps.

yes that is all you are trying to do, narrow villains range with each action he takes, and then play your range vs it as best you can. Very difficult to practice in real time whilst at the tables though, so doing this away from the tables will help you instincts

Flopzilla - play around with that program. start by getting a feel of what an X% opening range means. See how different ranges connect with different flops

Book ~ Let there be range~ , by Tri Nguyen and South maybe handy for the subject

Try to build very broad categories (like value vs bluff, made hand vs draw, etc) for a start and then try to reach greater precision step by step. Try to formulate hypotheses like "Villain is never betting worse than xx for value in this spot/ with this sizing" or "Villain has no possible blusffs in his range". Try to do this even if you have snap calls to get more feedback on your tought process.