There's a cool bit of magic where say you have 4 cards, 2 aces and 2 kings...you give the spectator the 2 kings and you have the 2 aces. A snap, and suddenly YOU have the 2 kings and THEY have the 2 aces!
It is taught on scamschool I believe. There are many versions, but Brian's is the best.
Honestly, the reactions you get from this are amazing! And this is not to mentally exhausting for the spectator, making it perfect for an opener.
You will also gain confidence after amazing them with this stuff. That should tackle shaking hand problems (I know because heck, I have them too!)
Aaaand...am still looking for the proper name of the above effect!