Re: starting a box
Advice #1, be prepared to be able to cover at least 6 months of the bills without any income from clients.
Advice #2, kinda leads into #1...don't get screwed on your lease payment for your facility. That's the biggest monthly expense you'll have so keep that in mind as you're searching for a location.
Advice #3, if you're 100% sure you're going to do this, start talking to people about it NOW. Get their interest up so they'll be dying to sign up as soon as the doors open.
I'll try to think of some more biggies and get back to you.