Concur, wear VERY comfortable shoes. I haven't been in a few years, but suffice it to say, the generally rule was:
Day 1 - Networking. Everyone is talking to old friends, and touching base with manufacturers; basically re-establishing contacts.
Day 2 - Making deals, working contract details.
Day 3 - Closing the deals, setting up follow on meetings, trips, etc.
By the end of Day 2, most people are either exhausted or severely hung over (or both). It's an interesting trade show, but if you're working a booth, it can be brutal.