5. Don't give discounts. When friends ask for your services, throw in extra stuff for them, but don't give them discounts.
Should be tattooed on the forehead of every babe of woman born. Give gifts, not discounts.
Discounts, however generous, however well-intentioned, just scream "HEY! YOU'RE PAYING TOO MUCH FOR THIS, STUPID!"
Learned that the hard way. Apparently everyone does.