You've decided you want to go to a conference.
Firstly, find a conference. Google it. Check out your local RWA, SCBWI, etc conferences or local writing associations for their annual conferences. Ask your writing buddies. Stalk local agents and see where they're heading. If you have a writing group in other parts of the country, set up a fun getaway with them and visit them in their home town or make a group trek.
Okay, you've signed up for a full weekend of fun, fun, fun!
You need to know the who's who of the conference. Who is the Key Note speaker? Are their books in your genre? Read them. Check out who the faculty is--agents, editors, authors. If you plan to pitch the agents, note their genres, their clients, visit their agency websites, Twitter, and personal blogs. Same goes for the sessions, lectures, and workshops you plan to attend--know who is speaking.
Will you need to bring anything? Lots of paper and a pencil sharpener. You'll be taking notes. Lots of them. Business cards, if you have them, to share with your new friends. It's a great place to network (more on that later). You don't need a copy of your ms, unless you're attending a workshop in which you'll need it. Note the materials the sessions/workshops ask you to bring and bring them (agents will not ask for your ms or any hardcopy--more on that later). If there is an opportunity for on-site consults with editors/agents for mss or query letters, take advantage, and note the deadlines or if you need to bring your materials. If you're able to sign up for it there, bring the materials in case you're able to get an appointment.
By the way, if an agent you're eyeing is doing ms critiques, it's a great opportunity to show them your work and garner interest--at the very least, if you revise and submit to them at a later date, they'll know the quality of your edits and how much you've improved.
Oh, right, one more thing. Preparing your pitch. Most conferences will have a "How to Polish Your Pitch" sort of workshop the first day (post on that later). Attend it. Prepare as much as you can before hand. You won't just be pitching agents. Every time you meet someone new, they'll ask "what do you write?"
Anything else? Yeah, prepare to kiss your old life goodbye. It's gonna be a wild ride.
How do you find conferences? Do you find that you need anything else to prepare yourself for a conference (besides a babysitter and a Costco box of 5 Hour Energy)?