As a student, how do I get the most out of the APA conference?
Maximize your chances of good things by thinking ahead. Go to the conference with three or four conversation opening questions pre-planned. Make and take business cards (Yes, "MCP Student" is a legitimate job title). Don't spend all your time in a huddle with students from your own university: that's not the way to meet new people (You can debrief with your friends later).
You can't become part of a community unless you step forward and try. New entrants into a professional group often feel that the group isn't interested in them. This isn't true. More likely, the person who walks away from you after you've just introduced yourself has something else on his/her mind: a presentation coming up, a must-make connection with a colleague, a phone call back to the office. There are lots of others who very much want to meet you, to help themselves expand their contacts, to learn what young planners are learning/thinking, because you are someone different than the people they see every year, because they themselves don't know anyone and feel excluded. Extend a hand, introduce yourself, ask a question. Even the overtures that don't lead to anything now may open doors later.
Objective Function: "Leave memorable images; take useful data (projects and contact info)." Look like the person you want to be remembered as. Say things you want to be remembered for. Bring home names and addresses, copies of good reports and remarks, ideas for things you want to do and behaviors you want to emulate.
Have fun. If you're in a good frame of mind, you will be more relaxed and function better.