These points are from a friend I met several years ago Gary North
the entire article is great on What WalGreens forgot! : http://www.lewrockwell.com/north/north346.html

So, for the benefit of sellers everywhere – and if you earn a living, you are a seller – here are the basics of successful selling. They all are an extension of this principle: "The customer, possessing money, holds the economic hammer."

1. Word of mouth is the most cost-effective form of marketing. (With the Internet, it’s word of mouse.)
2. The customer is always right, unless he is trying to cheat you, and even then you probably ought to go along with him anyway, once.
3. Identify your ideal customer, and structure everything that your company does to meet his/her demands.
4. If a price is listed, honor it – no bait and switch, no "that sale ended yesterday."
5. Offer a money-back guarantee or "we’ll fix it free of charge" (risk-reversal).
6. The value of a customer is the profit generated by the number of repeat sales (the lifetime value of the customer).
7. The first sale is the most expensive one for a seller to generate.
8. Profitability is in repeat sales (the back end).
9. Repeat customers are more forgiving.
10. Don’t carry a product line that repeatedly alienates customers.
11. Keep all sales records in a data base.
12. Use the data base to spot successes and problems.
13. Use the data base to make special offers to the ideal customers you want to return.
14. The customer evaluates the entire company through the people he deals with in the store.
15. Train your entire staff to understand these principles.
16. Create a system of ongoing rewards and punishments that reinforces this training.
17. Implement this system.
18. Begin at the top.