Selling is more about the offering of goods and services, where marketing should be a focused plan to find and contact specific prospects. Selling focuses on the needs of the seller, where marketing focusses on the needs of the buyer. If you find yourself talking to a prospective client and you're talking about yourself or your business, chances are good that you're selling. Instead, describe your products and services in terms of how they benefit the buyer. This is true for every contact with a potential customer whether you're talking across the counter, placing an ad or sending out a postcard.