i always, at some point, glimpse the card, in case something happens. that way, if the cards fall to the floor, i can pick them up and find their card again. then i usually move into a "mistake" trick.

jokes when someone is picking a card:
"pick any card you like, absolutely any one at all...." *spectators hand gets rite over a card* "... except that one. " *if spectator plays along* "or that one. as a matter of fact, it would be great if you would take that one."*point to a card. then, rite before spectator takes it* "im just kidding, you really can take any card... except that first one."

or

"oh dear, thats the card of death. oh well, i beter make this last trick a good one."

or

"be careful now, i coated all but one of the cards with tobasco..."

or

"you see how im fanning them here? thats possible because of a special powder that i put on the cards..." *spectator picks card* "...called anthrax"

if you drop cards:

"oh, i forgot to mention, these are compass cards. they are attracted to magnetic DOWN."

if you drop some cards during, say, an overhand shuffle or other move:

"oh, dont worry about those; this is a lepper deck.

When I mess up a trick I tend to pause for a moment creating some tension and make people hold their breath for what's about to happen, then I just simply say: "actually I don't have any idea what the H**L i'm doing..." And people laugh, and lets me move into another trick without having to point their fingers at me and laugh.

I like to say "now if i were David Blaine, this would be one of those tricks that get edited out of my tv special. But dont worry, I'll also perform the nearly impossible feat of eating lots of waffles while in a cardboard box FOR 24 HOURS!." (it should be noted that i lost my sanity about when i lost their card)

if i drop cards "hey look, my career is down there too!"

or just say something really odd and just ignore the fact that anything went wrong

umm... pull a sign or button out of your case that says "will work for food? ..."

OR

This is a fav of mine cause it's so versatile and everyone can relate...
"Everyone makes mistakes! That's why they put erasers on pencils."
It's a quote from The Simpsons said by Lenny.

dumb@$$

(when prop drops)Whew(whipe forehead) good thing the floor was there to catch that. (move to a trick that needs a voulenteer) Now who wants to be my next victem... Uhh i mean voulenter.

"oops..."

or

"This magic is a TRICKY business"

or

"CRAP!, that's exactly what I get for forgetting to sacrifice the chicken before the show"

Wow not funny ........... bet you feel stupied.

Wow not funny ........... bet you feel stupied.

good one

hehehehehe

Best one I've come across is Michael Finny's. He says it before he starts. "I am going to try a demonstration, and as you know, demonstrations often don't work and you won't be dissapointed." I love this because then if it does screw up, you can just say. "I said it might not work" and quickly move on.

If some cards drop..
"Thats ok, I am not playing with a full deck anyways... really, how many dropped? (they pick them up and count them and say seven or however many there is) And are any of them yours? No? What about any of the rest of these (as I turn cards face up one at a time counting from eight on through to fifty one)?" Their card is not there.
Now it is time to smile and be quiet, they will be looking around for their card which has completly vanished from the deck. The misdirection is perfect, I have control of their card and as they look and count the first dropped cards, I simply place their card into my pocket. It does not make sense in revealing their card because it has vanished.
Use those missed moments to become the magic... it is adlib and impromtu and I have found, that is sometimes the most memorable to the audience.

So many of these are great suggestions. But - if you're dropping you cards a lot then you might just want to practice more. It couldn't hurt!

Dropping cards is most of the time not due to technical skill but to your environment. You could be nervous, you could be trying a difficult move and somebody bumps you or something.
Sometimes things just go wrong. I carry an extra deck of cards in my pocket so that if i drop a deck I say 'Gazoontite?' as I take the deck out of my back pocket then continue the trick with the cards on the ground. I might even do a misscall then look at the cards on the floor and say '...well this is going well.'
It usually gets a laugh but I haven't used it that much.