The internet has made a huge impact. Most coin stores that have owners who are internet savvy sell online. Therefore a lot of the best coins are sold quickly to an out of town/state customer instead of a local patron. This is a two edge sword. It means the dealer has more money coming in which helps him stay in business but it also means you have to be quick to check his/her new inventory as the good stuff will always run away quickly when it is rare and priced right.
Telling your dealer what you are looking for is a great way to get to know them personally and build a steady relationship. Also having a local store is to ones advantage when looking to sell excess coins.
If those options are not on the table than maybe a local coin club where people can get together to buy, sell and trade amongst each other. If there is not one in your area try to start one by listing it on craigslist. Sincerely, John Leckrone