The key to direct marketing, like any marketing program, is to offer the right product at the right time to the right consumer and then provide excellent service so they will come back. Direct marketing doesn't work for everything. Your product needs to be something people want or need and can't get elsewhere cheaper or more easily. Present your product so the customer sees a use for it. There are two formulas that are part of direct marketing.
Prospects equals expense.
You spend money to produce a list of prospective buyers. This is one of your marketing expenses which will not be recouped in just a few mailings or a few years. Buyers equals profit. Once you have buyers on your list and you are providing service and products, they will come back to you and the profits will start coming in. You need a list of names of people to whom you can mail information or who you can telephone.