Once you've sold your product or service to a client, don't toss his or her name out the window. To build a strong relationship with your customers, stay in contact. Of course, you should notify them when you're having a sale or introducing something new. But you should also alert customers to seminars or magazine articles they might find relevant. And whenever you think of a way to save clients money or enhance their productivity, let them know. This will help position you as an invaluable resource. You're making them feel they can't do it without you.
The owners of a computer store that had both big and small businesses as clients knew that some of their homebased clients needed to be trained on their particular products before they could really make use of the systems they bought. So whenever they were conducting classes for their larger clients, they would arrange to have a few slots set aside for individuals who couldn't afford a private session to come and learn about their software and hardware. They would do this as a courtesy to the smaller client, and the large company was almost always willing to allow a visitor or two to sit in.
Excerpted from 303 Marketing Tips: Guaranteed To Boost Your Business