Follow the above advise, or do a few self working effects to throw them off. I love doing self working stuff for people who burn my hands because there's nothing to catch. Card to mouth is a good one as well, if you can do the necessary sleights PERFECTLY, otherwise forget it. I've forced a few hecklers back with card to mouth because once they know that you can do that, they follow things differently.
The only thing I can say that wasn't mentioned. Slow down. Get them involved. give them something to hold. Slow down. maintain consistent eye contact when talking. That's the best misdirection I can think of. Build rapport by looking them in the eye when you're addressing them, whether it be to hold out their hand or anything really... and when you need them to not burn your hands, address them. look them in the eye. do it on the off beat. Misdirection isn't that hard to pull off if you and your audience are comfortable and enjoying yourselves.
Try using some patter so that you are entertaining them rather than tricking them. If your presentation consists of the typical say-do-see (saying what you are going to do, doing it and then telling the audience to see what you have done) you are focusing on the trick and the spectators will focus on the method because there is nothing else for them to focus on. Also, try to make the presentation about them experiencing magic rather than about the fact that you are trying to trick them.
One of the few things that every magician should really know is how to deal with a heckler without losing presentation appearance (in bar scene or on stage). My favorite way is actually Sankey inspired by putting attention back on the heckler(s) in a comedic fashion. If they say something, ask them to repeat it. Repeating an insult is usually hard for most. Do a trick off beat, like the card in mouth, although if I'm doing a card routine, I'd like to do something a little more organic with a straw or sugar packet to change pace. Comedic anger towards the person, saying "Give me the straw, OH BOY, what I'm going to do to you!" and then proceed by doing a simple effect with it puts all the heat on the person. Everyone else is wondering what you could possibly do with the straw and after the trick everyone gets a good laugh, you maintain your magician character, you show something new, and you put the skeptics in their place.
On a side note if you DO want to get raunchy with them again credited to Sankey, I've done a quick countdown force that spells out F-U-C-K-Y-O-U, or DEALWITHIT. More appropriate in bar/school scenes when appearance isn't vital.
Don't perform to an audience that burns your hands and openly say that they are trying to catch you. In all cases you will lose. The magic is not the thing that should be performed when audience expects you to do funny moves, it's about naturalness of the situation. But that's just an opinion of mine.
Rarely are there ever people who stare at my hands or try to get me off my game. As i read your question again, what I'm obtaining is that you want some "trick" that's going to "fix" a spectator. No one will ever be able to straighten out a spectator out by doing just a "trick". Would you like to take a gander as to why? Because, magicians don't do tricks; dogs and hookers do tricks (especially the good hookers, man, do they do tricks!). Magicians perform effects by using proper apparatus AND (and this is the important part) utilizing presentation in order to: 1) magnify impact 2) secure proper understanding of what has occurred 3) a myriad of other important things that i will let you decipher yourself.
As usual, RealityOne is correct. You need to work on presentation in order to become a better magician and include patter to take the spectators mind off the method. However, if you are using patter and this problem still arises, there are one or both of two things occurring: 1) the spectator has had some experience that has molded them to believe that they can treat an entertainer in a negative fashion. Or the more likely of the two: 2) you're not a stable character. Period. You need to be a dominate character in your own goddamn show. You don't need to be offensive to keep them quiet. Sure, you can refuse to perform or simply ignore them. However, both of those "solutions" contain a rather large fallacy.
If you refuse to perform, well, that's just a bad situation waiting to happen. You can't get on stage, perform like a professional and then when you have some bastard in 3-15 yelling at you, just say "f**k you, the show is over." and walk off. No matter what setting you perform in, your spectators are making an investment in you. Simple.
The other popular answer is to simply ignore them. but, does that method work quickly or effectively? No. So why waste your time attempting it? For example, there's this ass***e that's been making some mildly offensive comments. You ignore him and have been for the past few minutes. Problem solved? No. what happens when he realizes that what he is doing isn't working? Chances are he won't stop; he'll move on to more direct applications such as "you're a fag", "let me see that deck" or my favorite, he'll slap the deck out of your hand to gain some sort of attention. Are you going to fold and take that? I sure hope not. Just my two cents, or three...
I feel like this is kind of a big concept but I'll try to keep it concise.
Something I feel worth considering is where is YOUR attention focused? A basic of direction is where you look, they look.
In performance you are, for a time, basically taking the lead in a social interaction. Among other things, it's up to you to establish where 'home base' is for the eyes. Ever notice in conversation with others we tend to talk 'at' a point in space? This applies to magic as well.
Don't want to establish your hands as home base? Whatever prop you are working with, take it out, then immediately drop the hand with it to your side and start talking to them, making eye contact and the like. Tell a story, talk with your hands and direct their attention to points in space with your hands, working predominately in the level that you want their eyes to be. Things like this will start to establish subconsciously that the home base isn't down at your hand level but instead wherever it was you wanted it to be. On top of that, you are training them to follow where you direct your attention. You've established that you do most of they talking, they do most of the listening, you do the directing, they do the looking. All before you've done any magic so this pattern is established before any major suspicions could hope to arise.
That's not to say having your hands burned is always a bad thing. Watch Tommy Wonder's Ambitious Card for a perfect example. You can see how he controls the attention. At one point you can see him basically coach them into burning the deck and being skeptical and he answers it perfectly. He performs it one way dispelling the possibility of him achieving the effect by a different method, only to use that exact method moments later.
If you can get your hands on Books of Wonder there is a ton of theory on audience management and performance to be had. You could tear every effect out of that book and it would still be worth it for the theory honestly.