Be careful about rules of thumb and conventional wisdom in your marketing. While some rules hold up time and time again, some don’t.
For instance: Noboby buys anything between Christmas and New Year’s Eve. Not true. I sold more than an average amount of books and services that week.
For instance: A guarantee increases response on websites. Well, this one is tricky. A good guarantee makes it easier for people to buy, because you take away their risk. But with the Internet (vs. traditional direct mail), you really need to test. Maybe 5 people in 3 years and thousands of customers have asked for a refund on my books, where I do offer a rock solid guarantee. But a much higher percentage ask for refunds on some of my other sites (ones that are less about me). There are lots of tire kickers on the Internet, and it is easy to get a free look at something, get your refund, and move on. So I’m testing no guarantee on some sites, and so far, paid response (net returns) is the same and I save myself the trouble of having to issue refunds.
What are other rules of thumb your own marketing has disproven?