Developing a brand and working off that idea is how one would start a full blown marketing campaign for a general marketing scheme. Spreading the brand via advertising in papers, online and through posters/billboards is the first step in generating buzz. Tell people what the company is about but don't give them too much information. Keep them guessing.
Create an online presence through social media and blogging so that you can build up links for the first page of Google/Yahoo/Bing to be filled up with when people search your for your company.
Wait for your clients to roll in.