To launch your business, use a combination of sales and marketing. For business-to-business sales, contact prospects on an individual basis first by following this sequence: Call, mail (or e-mail, or visit), then call again, and so on. Yes, you'll need a list, though you may be able to develop it yourself by identifying the companies you wish to serve and then contacting them to get the names of the senior-level individuals who are most able to make a buying decision regarding your services.
When you have your prospect list ready (at least two dozen names to start), contact your prospects by phone to gain appointments. Then follow up with literature as needed. Also, add the people whom you speak with to your in-house database and regularly market to them by mail as well as e-mail. Alternate phone and in-person sales contact with marketing until each prospect converts.