Written Publications and Marketing Communications
Brochures, flyers, and websites are all useful ways of letting prospective clients know about your services. You should let them know what you've done for other clients, and give them an incentive to contact you.
References are the most powerful form of marketing. When a client is satisfied with your services, they will let everyone know. There's nothing wrong with asking previous clients for referrals or referral letters.
Doing a great job is the best thing that you can do. Clients expect certain things based on your marketing materials, and you need to provide those services.
Learn more about letting clients know of your services and keeping your clients for the long-term in the full article (link above).
Blogged by Computer Consulting 101 Professional Kit