I only remember one concrete piece of advice from the book. In those days, the shipping and handling fee was where your profit was, but if a customer forgot to add it, send them the book anyway. You're not losing any money, so it's free advertising.
It did make me realize what I really needed to do. Unfortunately, I only got as far as the title, but I was proud of this title:
How to Get Rich Quick by Selling Get Rich Quick Books