I also don't want to end up wasting my precious school money for something that's gonna end up like Axis. And since we still don't know the details of this thing, I'll go ahead and make my suggestions:
-Make it clear when you are going to start, and start at that time. If people aren't able to register because of it, then that's okay because time is the most important factor in such a wide-scale tournament. It's the entrants' responsibility to come on time, it's your responsibility to keep things moving as quickly as possible.
-Use TIO and its TV assignment function, PLEASE.
-Even with the TV assignments, you will probably still lose track of TV availability at some point. Have at least two people ready to go scout the venue so they can verify TVs that are free.
-Keep Melee registration/brackets sepearate from Brawl registration/brackets. Try to have two of everything so that you don't have to do all your work in at one main station (people will swarm you).
-The WINNER of each match must confirm his own victory immediately after he wins. If he doesn't, then it's his fault for whatever record is made for him.
-Like everyone said, you need a PA system that can be heard throughout the entire venue. If you could get it outside, that would be even better. Hearing matches is a big issue at major tournaments.
-When people tell you they're gonna leave or go eat, write down their names, the time that they leave and how long they think they'll take. Then give them a little extra time to get back to their matches. You will probably have to disqualify a lot of people, but the ones who let you know beforehand should be able to keep their place.
-If you have a projector, don't use it on the "big boy" TV, because spectators are not your priority... organization is. People will be dying to see their bracket position ALL DAY, and if you just have a small computer screen then people are going to be crowding your bracket station like there's no tomorrow. I think you should have 2 of them so you can show brackets for Brawl and Melee at the same time. If you really want to show matches on them then get 4.
-Offer some sort of stipend for bringing set ups. It's a drag bringing your **** for a bunch of strangers to play on for an entire day, so offer some kind of motive/reward for it. This will ensure that you have plenty of set ups and it will make everyone happier.
-Make semi-finals and finals 3/5 games.
-Give players like 10-15 extra minutes if they need a break for back-to-back matches.
-Ask Race about getting food that is amazing and will sell out.
That's all I can think of right now but these things are extremely important.