As for how to get signed, how to further your career in the music biz, I got nothin. It's all been said a million times over, consider it on the same level as winning the Lotto and that's pretty much it. The real sad problem is you're either playing gigs like these a few times a month or you're a superstar making millions. There's not much in the middle any more.
As depressing as it might be to hear I think Bob has made the best point with his Lotto analogy. There are VERY FEW signed artists and even fewer who are signed and making it big. Yet there are millions of folks out there vying for these few spots. And probably hundreds of thousands are actually damn good, well connected, living near the epicenter, etc. So do the music because you love it and buy a Lotto ticket from time to time (but don't bet your retirement on either!)