One of the resources and tools i used in my search for a literary agent was the website QueryTracker.net. They're a database of literary agents, through which you can search for agents and publishers who might be interested in representing/publishing your work. You can search on variables like geographical location, genres/types of writing represented, and so forth, and also research who represents whom. (Got a favorite author but don't know who their agent is? QueryTracker is one way you might find out.)
You can join it for free and use it with limited functionality, but membership is only $20/year, and that allows you to rank the agents you might want to query. I paid the fee because in my research, i found dozens of agents who, at first glance, seemed like good prospects, but the more i looked into them, the more i wanted an easy way to see which ones might be first choices, second choices, or maybe-if-i-don't-get-any-interest-from-others. So, i'd put agents on the general list, then i'd Google them for interviews they might have given, look them up in the 2014 Guide to Literary Agents, check into their preferences and bios on their agency websites, etc., and rank them further.
Well, when I checked into QueryTracker.net after signing with Jonathan Lyons of Curtis Brown, Ltd., updated my status as having accepted an offer of rep and closed out my project's query list on there for THE DECADENCE PAPERS, i agreed to do a "Success Stories" interview for them about how i used their service in my search for literary representation.
That interview went live on their site last night, and you can now read it online here. Lots of great background info about the querying process, THE DECADENCE PAPERS, and even a sample version of the query that yanked me out of the slush pile!