Coin Shop Cherrypicking

Know your owner well, so they trust you to go off in the corner with coins. They will also know your looking for varieties, and pay their full price when you find them (be open and honest). I've left not buying a coin because it's priced too high. I left a 1939S-1MM-002 yesterday because I thought $60 for a MS65 RB was a bit much. Sometimes they will offer a lower price, if I tell them, "I think this is a #$%^%," and not buy it.
Many shops are primary bullion buy and sell. If they're busy don't take up their time.
I take in great coins offer to sell, not intending to sell them; so the shop owner knows I'm a serious collector. This can start a relationship. My 1885 Cameo proof nickel or MS 1916D dime usually do the trick. Also, the 1955 double die opens their eyes. Ahhh the days before the rise and fall of silver and gold!
You people have any ideas?