I've been kinda training Lacey to nod her head yes and shake her head no using a clicker. She's caught on really quickly.
If you're really interested in it I'd suggest reading lots of books about clicker training dogs and cats (maybe your library has some) to get the feel for clicker training and how do do it properly. I read a few books about clicker training horses and I found that they missed Karen Pryor's (the "inventor" of clicker training) points about how to make the training the best and easiest for the animal to understand.
I've been doing less of it lately though because it's pretty hard to remember to slice an apple or cut up a carrot before school so I have it when I go see her (I started using grain but having grain leftovers in your pockets after they come out of the wash is gross haha).