I believe a very underused principle in magic is that of the auditory nature. I don't just mean stuff like the click pass and Gertner's Steel and Silver routine. I mean letting the effect really sink in by showing something supremely solid
and have weight. A good example is the video below.
Yes... I am a whore. Why do you ask?
Regardless, this effect is NOTHING without tapping the card on something or, ideally, dropping it onto a hard surface. (Of which none were available for this video) It's the noise that really fools them. How does it fool them? Simple. People make assumptions. They see it LOOKS like wood and you might say it is, but they don't fully believe it until they HEAR it's wood. There are a few magical items like this out there, that need to be seen to be believed.
A prime example is the Heavy Deck that has been released and knocked off. A huge hunk of metal that looks like a deck of cards, for those who don't know. A card is selected, then found, and then the deck is handed out and found to weigh a fuckton. The rub in this effect is that you drop the deck onto a surface first, especially if you are performing it for a group of people. With one person, you can get away with dropping it into their hand. It will lose some punch, but it becomes more intimate with one person, so the rules change a bit.
If you are however doing this effect for skads of people, dropping it on a table is a MUST as everyone will turn their head as they can't believe what they heard. This is an effect where assumption is reversed. They don't believe what they just heard. Maybe it was you hitting the table or just them having a lapse of hammer and anvil oddity. They will then want, nay HAVE to pick it up to see. When they now feel how heavy it is, they will be fully astounded.
There are a lot of great ways to use audio to your advantage for not only magic but also comedy. We have five senses, let's use them all. I know some of you might be senseless, but in the long run, it only makes sense. If yer lucky it might just make you some dollars and cents. So don't be shy, let em' hear yah commin'.
Aural sex: It's your friend.