If I see a guy do something once, it often means he'll do it again.  Most people don't often realize they are doing what I would call "the same thing" and they keep doing it.

For example, a player might raise preflop, then check down K hi.  Four hands later he might do the same thing, but with ace high, and not really be thinking "he just saw K hi a little bit ago, so he might put me on K or A hi here" he might just be thinking "high card, position, he won't bet if he doesn't have anything I hope, just gonna check down."

That's not the best example, but this second example is better stuck in my head at the moment.

In other cases, I can assume an opponent is doing something because of something different that he's already done.  In this case, I don't think anybody but very thinking (not necessary very best, but just very thinking which often correlates with very best) opponents pick up well on this transparency.

A common example for this one is the player that donk bets their strong hands OOP.  It's a very bad thing to do, but I find opponents like this once in awhile.  They call my PFR, then the only time they don't check is when they have a strong hand.  They bet out, and unless I have good odds on a strong draw or a strong hand myself, the proper play is to fold.  Now, when they check, this means their range is very weak.  Since I can eliminate most, if not all, strong hands from their range, when they check they will have at best a medium pair, and usually nothing.  All of that can usually be folded out anyways, at least at a very high success rate. 

But it's a result of him showing me how he plays a certain part of his hand range in a very certain way, and it makes other areas of his game very transparent and easy to play well against.

Also, for "when to turn bet" and adjustment type stuff, you can read over this recent thread too, it's pretty solid: http://www.husng.com/node/1860