They say that finding an agent is a lot like dating. These days, it's a lot more like online dating, to be precise.
And like online dating, there's a slew of info out there about how to do put your best face/foot forward while trying to get your dream agent to commit to you. You've got to hook them with a great pitch (your query letter), get them to read your fabulously written book, and pray that they love it! Oh, and ideally not be a crazy person. There's some luck involved, but it's mostly chemistry (between the agent and your book, of course).
Then HALLELUJAH -- an agent offers you representation.
But what the heck happens after you sign with an agent? Sure, we'd all like to think you two ride off into the sunset together, on golden-horned unicorns with seven-figure book deals sprinkling down from the sky. Happily. Ever. After.
But let's get real. That's not how the world works.
There's a good chance your first book won't sell. Or that your agent might not be the perfect match for you after all and decides to leave you (or vice versa). Or an editor who loves your book gives you an R&R but then the book dies at acquisitions!
What do you do then? Who do you talk to? Ranting on Twitter/Tumblr//Facebook that LIFE ISN'T FAIR NO ONE WANTS ME just doesn't generate that many "likes" (or sympathy), so I wouldn't advise it.
When I first signed with my agent, I came across Natalie C. Parker's Agented Author Hook-up -- Natalie, an author herself, had the fantastic idea of grouping agented authors together so they can support each other. It's been a tremendous help for me as someone transitioning into becoming a writer, and it's always great to make friends who are going through similar things as you!
AbsoluteWrite and QueryTracker also have fantastic forums for writers in agented (and non-agented) purgatory. For those on submission, Natalie Whipple's articles "What to Expect When You're Submitting" and "What Happens When It Is You" are not to be missed. Also check out the SHIT series on Writer Writer Pants on Fire blog, headed by Mindy McGinnis.
And when you're through with those, there's always getting down to business and working on the craft. Vonna Carter keeps a thorough list of workshops and conferences. Even if I don't end up attending any, I browse through the list often to read the workshop titles -- sometimes they inspire me to work on something in particular in my own writing, like honing my characters' emotions and arcs, plotting, and voice.
With all that said, don't get me wrong. It is an amazing feeling to have someone in the industry believe in you and guide you along that exciting journey to become a published author. Pat yourself on the back for that accomplishment.
But at the same time, don't get too cocky. Keep writing, even if you sell your first book or even if you don't sell your fifth. Keep writing, and keep learning.
Your agent will appreciate you for it.