My advice is not to try too hard to sell to people who are
1. Lawyers - they are trained to look for the source and will never be satisfied with any price an established dealer offers. They will always feel that the price is too high.
2. From the Netherlands. The greatest traders in the world. Let's face it - their country would be 10 feet underwater if they did not use their shit to build it up for the last 1500 years. They just are too tough. They made one of the great nations of the world out of shit. Sew your mouth shut when they come into the gallery.
3. From Massachusetts - Too tough. This is a mystery to me because their history is amazing. Maybe my passion for the Yankees automatically disqualifies me. It has been very frustrating because they tend to be very well read and know their American history better than most other Americans.
4. Work for Goldman Sachs - While they are politely speaking with you, they really are thinking - "Where can I go so that I can buy it and sell it to you and double my money." When God imbued these fellows with their talent to make vasts pots of money, he took away their ability to comprehend aesthetics. Most partners would be better off blind. At least then there would be a better chance that their trophy wives didnt always look like younger versions of their first wives.
5. Are artists themselves. Love what they make not what others create.
6. Are art dealers. They come into the gallery and are only hoping that you will flap your mouth and give them information they can use to benefit themselves and cut you out. Do whatever it takes to get them to leave. Never respond to their letters, e mails, phone calls or personal entreaties.