I did it for a year. It was a good position. Most important thing is to communicate with the day pharmacists and find out what they want/expect of you.
Hmmm.. Can't think of many tricks off-hand. Know how to check if an Rx was picked up at another CVS or not, and how to charge people their copay amounts before you can bill the insurance (and remember to follow up with the other location in the morning, so they can reverse the claim and you can bill it). Feel free to PM me with questions.