Well, it`s hard to start a digital label, unless you run it off the back off a physical label.
My advice is to put money into promotion, which is the hardest part of dance music mp3.
It`s harder to get DJ support etc
So magazine ads and ads on other websites, free links etc will help immensly.

There`s a very obvious (but tired) route of getting some big names on your label to essentially "Buy" their audience, but people aren`t stupid and these days, they follow the producer and not the label most of the time.
For example, you get dave clark on your label, people go to the label for the dave clark track, next month those same people go for his track on another label, as it is his name they are putting into the search engine.
Nah, I reckon your better off going with quality material from the onset, regardless of name, you`ll get more respect and peace of mind.
Good luck, and be sure to get you label supported by as many online sellors as possible (assuming you are even going to do it commercially)