Charles Stross has some excellent advice on Readings. Check it out.

A friend, who recently sold her first novel, wrote to me paraphrased: “help I’m supposed to be giving a reading from my work at a science fiction convention. What do I do?”

Readings, like signings, are one of the epiphenomena of writing: not a central part of the business, but people give you funny looks if your first reaction on being invited to do one is to shriek and hide up a tree.