Here are some suggestions from my years of Tech-Eds:
1. Bring moleskin for your feet, and use it prophylactically, before your feet get blisters.
2. Bring a power strip; you will make many friends in breakout sessions.
3. Bring a decent backpack. Sometimes the Tech-Ed backpack is good, and sometimes it is weak. Don't gamble.
4. When I was in New Orleans, the breakfasts were dismal, while the "special meals" folks lived high on the (figurative) hog. So I signed up for special meals, just in case. Not saying everyone should do this, just sharing a personal best practice.
5. You don't necessarily have to be in the keynote hall for the keynotes; you an find a comfortable spot outside and watch it while doing other stuff.
6. Don't fret so much about taking notes; you can download the powerpoints and session videos soon after the session itself. Even so I often take notes to make myself pay attention.
7. I always have a bittorrent client running for Grateful Dead and other (legal) live music torrents. Legal though this may be, it can get your machine blacklisted from conference wifi; be sure to turn your bt client off at the convention center.
8. Expect great things.