Drink plenty of water- There are a number of water stations located around the convention center. Keep yourself hydrated.
Eat- Never drink on an empty stomach. A smart idea is to make a necklace of pretzels to snack on.
Wear a costume- It is fun event so make the best of it.
Don't drop your cup- Not only will you not get another one, you will be embarrassed when the entire festival goes into a short uproar. The floor is concrete so it will echo for everyone to hear. Keep your hands tight around it.
Pace yourself-It is marathan not a sprint.