This is how I distress my mantle and it's so easy! How to "distress" painted wood furniture. The technique she uses is a little different than what I've done. Looks easier.with a little less dramatic of an effect.
Wipe vaseline on the base coat before adding your final color to help with the distressing, then lightly sand those areas to reveal the base color. This is dark walnut, but an aqua or mint green would change it up too.