Here's a scattering of agent tweets I've seen on this topic lately:
Why shld you read from pub before sub'ing? To know if your story fits, to check out their quality, their editing, their formatting//What if you're submitting to a place you'd be horrified to have your book associated with or that doesn't do quality work?// Throwing it at the wall to see what sticks isn't a good publishing plan for any author. Do your research!
Why this matters: Let's put this in practical terms: If your desire is to teach, would you apply for a job as a deoderant tester? If you are gifted in mathematics, would you actively seek a job as a makeup artist? Would an experienced prison warden actively look for a way to work arranging choreography for the Bolshoi Ballet?
Of course not. (Not unless you're looking at one of those as the potential lead-in for a great fiction piece, in which case - be my guest.)
Further, there's the point made in the second tweet: what if you show up for work to find you've landed with a bunch of prissy neatnicks when you're the tomboyish mountain girl, or a bunch of hard-nosed thugs when you're the prima donna? Remember that if you land a job with Agency X, then their website, and other workers associated with them, become part of your collective public image. You need to know before signing your contract whether you're OK being known as part of the Neatnick Wilderness Thug Girly-Girl Collective before you send those business cards to the printer.
The same applies with whom you query. Consider it as a job interview for your book. If that is so, then your query is your job application, so you want to make sure it goes to the right office, the best prospective employer.
To help narrow down the possibilities of whom you should (and should not) query, I would highly recommend Chuck Sambuchino's 2012 Guide to Literary Agents. Not only is it full of great listings, but also contains a very informative FAQ section at the beginning that gives more clarity to submissions, what to reasonably expect from an agent (even after you get signed), the question of critique fees, and the rest. For those of you who have Kindles, this book is also available as an e-book for only $9, as opposed to the usual $20. (Nice deal if you ask me --- that's how I came by a copy.)
Of course, once you think you've narrowed down who you want to query, make sure you go to the next level of preparedness, and do the following:
* Go to the agent's website. Again - if we're talking about potential employers, you'd want to know a little about who they are, what makes them tick, and the kind of books they have represented in the past. Also: If you've been "handed" a link to follow, doing your homework and finding a rather unprofessional website can be your first red flag that it isn't a reputable agency for your manuscript. (I've seen a few of those. They're creepy.)
* Double check submission guidelines. Sometimes agents will tweak what they are looking for, which means certain genres can roll off or on the menu at different times. Don't assume that an agent always is looking for paranormal romance, or high fantasy, just because they have in the past. Publishing trends are constantly shifting, and unless an agent sees themselves as serving a very narrow and specific niche (I don't know of any like that - do you?), then they will generally close or open submissions to certain groupings of literature according to what they are certain they can sell.
* Don't overlook "annoying" submission requirements*. You're sending your query to its first job interview. Make sure you tuck in its shirt, zip its fly, and wipe its nose nice and clean before you send it in. (Or, put more practically, make sure your query is in the correct format, and within the specified parameters. If the agent says "Send the first three pages in the email - no attachments" then do just that.)
*Topic of a future Agent Tweets post.
Do you have a favorite online source for writers wishing to narrow down the field of agents?
If so, let me know in the comments?