Controlling distance and feints are what gets people second guessing their attacks. The jab and use of feints is very important, helping you to break them down and adjust to their style, where you can then let off with body head combinations.
Watching the breakdown of marquez vs. pacqiauo 3 is a great example of the feints that marquez uses to control the action. Another good example is the Hopkins liver shot knockout of Oscar, where Hopkins feinted a right hand a bit subtly, Oscar raised his arms thinking a right was coming up top, and Hopkins hit him with the hook to the liver.
When you see a fighter who is throwing less punches than in his previous fight, it is often the result of the other fighters use of feint and counters. PBF money makes all his opponents drop their activity level, marquez did with PAC in their 3rd fight, and Martinez was hard to catch with his constant movement and misdirections against Chavez jr, who really didn't do a terrible job of cutting off the ring, but the experience and speedy footwork of martinez made it hard for him to get set and land his sitdown, flat footed punches, which he needs to do to be effective with his game.
Main idea is to give the opponent different looks, be able to switch it up, jab, feint, and mix up body head head body combinations.