Take a look at this thread regarding overly dry or moist hands: http://people.cs.uchicago.edu/~alain/ma ... hands.html
As for strengthening the muscle at your pinky base, David Stone had a good idea, that you can stick a beer bottle (or root beer whetever) over your pinky and with your hand palm up, lift your pinky up and back down like weight lifting.
Also just having coins nearby and palming throughout the day will make the palm feel more natural and develop the hand motor skills used in palming.
For more tips on the classic palm check out www.coinvanish.com
in the "Foundations section" for an essay on how to palm a coin.
Good luck with your coin magic.