The biggest single design mistake that people who run technical conventions make is failing to promote after-hours social interaction. If people just dissipate after dinnertime for lack of a place to find conversation, that's a sin and a waste. At some SF conventions the con suite never closes. The con suite should feature lots of places to sit. It should have sodas and snack food, and perhaps beer.
Informative signs are vastly more important than people usually realize.
Your event won't work if the attendees and staff can't find things. Each program room should have a sign listing its event times. Key locations like the con suite, convention ops room, and green room should be signposted. The registration desk should have a large sign nearby featuring a floorplan of the public areas.