Conferences are a great career opportunity, both in terms of learning resources and the chance to make lasting personal and professional connections with people in your field. But that's all a little daunting if you're new to the field or put off by the idea of "networking," so I've put together this list of some ideas to help you get the most out of your conferencing experience.
Ruby and RailsConf have a scholar/guide program to pair people new to the community up with more seasoned conference-goers. I'll be serving as a guide for the third time next week, so I'll share some of the knowledge that I've shared with and gained from the scholars I've met through the program.
I'm writing this guide with the tech conferences I've been to in mind, but the advice probably applies to other conferences as well.

Strategize
For a multi-track conference, there will be lots of sessions going on at the same time, so get at least a vague idea of what sessions you'd like to go to when. Keep in mind that at most conferences talks will be recorded, so if there is a mix of workshops and talks, you're better off going to a workshop you're interested in and getting the hands-on, interactive experience and catching the talk on video later. Keep a list of the talks you want to watch later so you don't forget by the time the videos come out.
It's also all right if you don't want to go to a talk during every slot. You can find a quiet place to process and synthesize what you've heard so far or hang out in the hallway and chat.

Know your limitations
Conferences are exhausting. It's okay if you don't have the energy or focus for a super-technical talk late in the afternoon. Or if you know you'd rather watch the video later so you can pause and rewind. Maybe you aren't big on after-hours events. Or maybe you are but you need to catch a nap first. You're allowed to come and go as you please to get the most out of your experience. That includes leaving a talk in progress if you're just not feeling it.

Put the laptop down
I know, you're at a tech conference, it's counter-intuitive. But instead of looking things up as the speaker mentions them or trying to type notes, write down notes or live-tweet the talks. The exception to this is in workshops where you're actually writing code as part of the exercise.

Tweet
If you're taking notes by hand, highlight important points to tweet during the breaks. Otherwise, live-tweet the talks you attend. Make sure to take note of or find the speaker's twitter handle if they have one. Also use the conference hashtag if there is one. This is a great way to engage with speakers, who will appreciate hearing what points struck you most, and is also a great way to engage with other attendees and the tech Twitter community at large.

Have 1:1 and small group interactions
Going to the same conference with hundreds or thousands of other people feels intimidating, so make sure that you're getting some time in smaller groups. Chat with someone at lunch or get a group of a few people together to grab coffee or dinner. This will get easier as you attend more conferences as you'll begin to see familiar faces.

That about sums up my advice. Have any comments or ideas to add?