Remember that when you're trying to sell content to a customer, they're just like any other consumer: they're just weighing the cost/benefit of making a purchase. They're debating whether or not this purchase will help them and their business. You already know that the information you provide for your clients must be fascinating, educational, and relevant, as well as make your clients appear trustworthy. It also needs to be written in a way that allows for conversion. It must be written in a web-friendly way as well.