If you want to use stain on your signs for a little bit more rustic look always apply the stain AFTER you apply the lettering! If you stain first and then apply the lettering it will be very difficult to get the lettering to stick and you will most likely be very frustrated!
I like to you cheese cloth to rub the stain into the wood. Go slow and be gentle so you don't ruin your lettering.
A little stain goes a long way! Don't over apply:)