Patience, persistance and slow, methodical searching is the right attitude to have. Be sure you are hunting older areas too. I've been hunting a friend's yard, the house was built in the early 40s. I pulled 22 wheat pennies (with that many wheat, there has to be silver somewhere...), 4 clad quarters, 3 clad dimes, 1 nickel, 5 memorial pennies and pockets full of trash before I got my first silver dime, a 1959. I know there has to be more there, I just have to remain patient and persistant in my search.