In the book The Course by Ed Miller, he recommends including hands like A5s into your 3-bet range to balance your range. Are you supposed to show after successfully bluffing? If you muck, then your opponent may just assume you had a premium hand. If you show, then low stakes players may assume you bluff frequently and start calling down a lot more thus forcing you to tighten your range.
I never show after successfully bluffing, unless it is a friendly home game and I want to mess with my friends. In live games at a casino, I find it is best to keep your opponents guessing what your hand was. Some opponents may assume that you had a premium and move on, others may not be too sure about whether or not you were bluffing. Either way, this maintains the image that your opponents had already assigned to you.
Showing can encourage your opponents to call you lighter in future hands, but I find that this is not super necessary in lower stakes casino games. Usually the opponents are calling often enough anyways in the 1/2 and 2/3 games I play.