Well, the concept apply to all industries. Advertise!
You need to get some advertisments in your local papers, directories, yearbooks, etc. Make some flyers and pass them out to local business'. Write a letter about your services and personally address it to local business.
You also need to promote your Web Site so people can find it easily.
Another way to get clients is to offer a company with an outdated Web Site a new, and improved, Web Site. This is done via a Web Site proposal.
Well Buntine is certianly right... 100% you have to spend money to make money, that "money" can also be considered time.
If you know you can get the job done and make your clients happy then I would suggest spend as much as your comfortable with that you can consider as investment.
At the same time what you've been doing is Networking to get your clients and that might be your best bet for more work. Referrals make the world go round, ask your current clients who they know and might like a new or redesigned site.
I could ramble on and on... however the key is finding what works best for you and your target market.
Taking an ad out in teh local paper is surely an option... but why not take a more targetted approach.
Get a post card or a letter made up that details your services and send them to clients you would like to work for in your area.
The paper is so wide open that your target market may not notice you and unless you advertise on a regular basis your not going to get the results your after.
Also loook for advertising that's not the normal routes, here we have a company that does indoor advertising in the rest rooms and gas pumps. I currently have and ad for them and with enough time and exposure it's going to pay off nicely.
Be sure to emphasise the cost effectiveness fo your services and you should get a pretty decent response from a direct mailing campaign. Make sure you address each letter personally (not "Dear Sir" or "Dear Business Owner").
I got a pretty good response from this when just starting out is business and it certainly led to other things.
Calling companies seemingly out-of-the-blue, or, in other words, calling companies that your research shows may be interested in your proposition. Getting it right is an art -- don't just call random numbers and hope for the the best.