Take some time to read through Poets & Writers great article on literary agents. Every author seeking an agent ought to read this information at least twice. It tells you everything you need to know, and should take a lot of the anxiety out of starting your agent hunt process. Too, it’s chock full of resources you can and should explore at your leisure. P&W even offer database of agents one can sort through by genre, though how up to date it is, we can’t really say.
Once you’ve looked at the PW article, click over to Write It Sideways, which has a great blog post specifically on query letters and literary agents’ lives, that we heartily recommend. This post will ease you into looking at things from an agent’s perspective, which can really help keep you from making all the rookiemistakes when you do begin your search for an agent.
Take what the post says seriously. Two months to craft a letter is not a joke. Especially if you’re the type that likes to go after the top dog in the fight first.
Some people “tackle the giants” in the game after they’ve practiced on lesser known literary agents. Some people go for the top gal (or guy) straight out. Whatever your strategy, make it good letter every time. Because you never know where it will end up.
You may make a good impression and be just the sort of person the agent likes to deal with, but your work is simply not be what he or she handles. In that case, you might be tossed as a bone to another agent in the same company, an up and comer in the same agency, or even a more senior person, or even to a different agency altogether where that guy/gal who read your letter has a friend.
* beautiful art by http://www.oceansbridge.com/