1. Keep your fingers crossed.
(Why do you use this expression? When we wish somebody good luck, we keep our fingers crossed. Why do we do that? Do you have some reason for that?)
It's an old superstition!
http://www.google.com/search?hl=en&q=keep+your+fingers+crossed+origin&aq=3&aqi=g8g-m2&aql=&oq=keep+your+fingers+&gs_rfai=
(Skip the second link in here and read a few others!!)