Hang the shingle out and wait.
Guess what, they won’t come and the phone won’t ring. The same is true for your website – even more so. You won’t exist. Netcraft says there are currently over 109 million websites which compile over 30 billion pages. At least with retail there’s a chance people will walk past!
Start up advice is this: People don’t know and people don’t care unless you make it so.