There's no set program or course for someone to take to become an agent. You usually mentor with someone who shows you the ropes, watch their successes and frustrations (and in publishing today, there are a lot of frustrations), and then one day, you know you are a real agent - sort of like Pinocchio becoming a real boy.
Sandy Lu has been working with me for quite a while, making connections and plowing through hundreds of manuscripts, editing and shaping. From the day she got this one urban fantasy in, she told me that she was going to sell it. She loved it, and editors seemed to be getting back to her much quicker than usual.
Then last week, she closed on a nonfiction title at the beginning of the week, and turned the one-book urban fantasy offer into a three-book deal. Champagne flowed in our office. Sandy had arrived!
She's on a hot streak now. And I'm really thrilled for her. There's nothing like calling a first-time author and telling them they'll be published, especially when the two of you have worked on the book for a long time.