My most successful marketing is working by referral. I belong to a referral group called Business Networking International, and by far it is my most productive form of building clientele. The idea is to build business relationships with other professionals, help other businesses by giving them referrals and, therefore, they become your sales force as well. I not only get quality referrals, but I also have people I trust in business to refer my clients to. There are many other referral groups out there; research and find one that fits you.