In one word: Publicity.
Nobody is going to know about you if they never see you anywhere they normally look. This includes TV, the internet, magazines, billboards, and so on.
If you can get a BIG section in a magazine by really impressing them with your music, then you might be able to get peoples attention enough - if you can, get them to put a taster CD of your stuff on the front cover, or as an insert on your page. That way if people like what they read about you, they can hear you too. If they like what they hear, then job's a good'n as my foster dad says.
To get you some good slots in magazines and TV shows, you might want to get a publicity agent. He'll also get in contact with various labels, and he'll talk to contacts in the industry to stur up some noise in the scene. The desired effect there is to have the record labels know who you are before they even meet you, but this sometimes doesn't work.
The internet is fine to use to get your music "out there" but actually drawing in listeners is the hard part. If you DO get a chance to be reviewed in a magazine though, ask them to advertise the address of the website where all your music is at.
Hope that helps.
