Colin was on mark when he said that you must practice in such a way that allows the handling to become an automatic action/some thing you needn't think about.
In the martial arts world we would teach newbies that throwing a kick properly 100 times programs it to the body's memory but throwing that same kick 1,000 makes it a matter of nature; there is not thought in the process, the body will do what must be done. Same is true when it comes to all aspects of magic and effective handling.
Misdirection is a unique skill in that we must each find our own footing based on personality, energy level, etc. If however, you are the sort that has a high level of "bouncy" energy and are able to jazz your audience, you can get away with some crazy stuff (just watch Goshman doing his Bowl & Sponge routine). Even on stage there is a truth to this; Blackstone, Sr. used to produce an elephant on stage in a puff of smoke. There was not big box or anything it was pure misdirection, the same thing exploited by Franz Harrary when he made a Piper Cub air plane appear on stage. . . there's along list of of examples but in each case you will find hundreds if not thousands of hours poured into learning every nuance involved with the desired out come.
"I Did Not Mess Up" are the famous last words of the world's worse magician. . . whenever their is failure in an effect IT'S OUR FAULT, end of story. We may not have blocked things out properly, we're not watching our angles, our patter is weak or, as you have tabled, our ability to get the audience to focus where we need them to during that covert action needs some direction . . .
"Direction" is the key however. Find a handful of people you trust, ideally a couple of non-magicians with strong theatrical background as well as a couple of magicians that are solid technicians with a real world working resume. LISTEN TO THEM when it comes to their guidance in how to make the effect stronger and it will get you there.
Best of luck!
