The folks at Internet Evangelism Day.com (yes, that's its name) recommend that Christian writers utilize advertising to better sell their 'product':

The press and advertising copy-writers have many years of experience in communicating effectively through print and graphics. We ignore these lessons at our peril. This does not mean that we should use worldly underhanded methods in evangelistic writing. Much advertising copy is designed to make people unsatisfied with their current lot in life and then offer satisfaction and fulfillment only in association with the product. Hey, wait a moment... Of course, done in a worldly way, advertising strategy is to rob the reader of self-esteem (no-one has a kitchen/family/appearance that good) and then offer the illusory dream of happiness only when the product is purchased.

However, we should look at the practical side of copywriting. These rules are validated by research done by advertisers, and come from the classic Confessions of an Advertisng Man by David Ogilvy, still easily available secondhand and libraries.