How did you fix your valve cover leak?

Guys/gals: The valve cover gasket on my 1974 225 slant six leaks. The valve cover itself is not bent or deformed. How did you eliminate your valve cover leak? Cork gasket or something else? Did you use RTV on the cork gasket before you installed it? Tired of cleaning oil off my garage floor. Please let me know how I can permanently eliminate this problem. Thanks!