One of my PhD students is on his way to his first academic conference. Conferences are one of my favourite parts of research: I've met so many interesting people and started so many fun collaborations that way.
Just today I saw this great advice from Michael Ernst about attending conferences. His advice is so good, that I've only got one thing to add.
Here's my tip. When a big group students from the same institution go to the same conference, they'll often hang out together all the time: at meals, coffee breaks, etc. This isn't a great strategy on their part, but you can exploit this. Once you make friends with one person in the group, now you can go with your new friend to lunch with everyone else in the group. Voila, now you have a network!
This is a general principle of networking (horrible name, but incredibly important if done honestly and well): Cool people will help you to meet other cool people. And once you've been around long enough, you can return the favour!