On his blog, Alan Rinzler interviews four agents ...
What’s the most important thing an unpublished writer should do to get an agent?
Candice Fuhrman: Write well! Then seek referrals to agents from other writers who are pleased with their representation. I would submit to a number of agents simultaneously (even though many agents say they don’t “allow” this). If you’re good, you’ll have several agents to choose from and you can decide who is the best fit for you.
Visit Alan Rinzler's blog for the full interview.
Also, I found this intriguing marketing idea. Got a book coming out? Why not throw a party! (Okay, something like this might only work in New York City.)