I'll admit, I haven't been to as many writing conferences as most of you probably have, but it's crystal clear to me how important it is that you not only show up, but actively participate in as many conferences as possible.
I know it may seem like you're just one of many little fish in a huge conference, but it's easy for you to change that. The first step is to go to workshops you're actually interested in--that way, you'll have something to say or questions to ask.
That's another thing--make sure you go with plenty of questions ready! If you have a particular aspect of your writing you're trying to improve, plan out the questions you think will give you the most helpful answers. If you're going to a lecture, jot down questions as they speak so you can ask them at the end (or when you 'bump into them' in the hallway :D)
If there's a newly published author there and you'd like to go to their workshop, read their book beforehand. Even if the workshop isn't about their book specifically, believe me when I say they'll be referencing it. Knowing it will also give you more opportunities to ask questions and comment.
Sign up for pitches and any contests available. Go with a goal in mind. If you don't have anything ready to pitch, most conferences have short story contests that you can participate. It's fine to just go and attend workshops, but you'll get so much more out of it if you're actively working towards recognition.
Mingle with people outside the workshops. There are plenty of people in the hallways, including published authors, agents, and editors. You may not even know that who you're talking to is an agent. So NEVER say anything like, "Yeah, my book's not that good..." Talk it up as if it were the best thing in the world, and be interested in the other person!
That being said, always be ready to elevator pitch your book!
Not only will these steps help you meet more people and become a little more 'immersed' in the writing community, but they will enable you to take more from the conference (remember, you're paying for this!) There are so many people I know who've met their agent or editor at a conference, and they weren't necessarily participating in pitches. Magical things can happen in those halls, but only if you're ready for them.
What writing conferences have you gone to/are you looking forward to? Do you have any great stories from conferences?