1) Exercise Your Dog - Usually July 4th leading up to the fireworks, the day is full of friendly gatherings, swimming, parades, and cook outs. Use this time to get some quality outdoor exercise time in with your dogs. The exercise is not only great for their health, but they'll be more focused on resting after a fun day than they will be on their surroundings.
2) Provide A Safe Place - When dealing with loud noises, many dogs find comfort in a secluded spot. Consider moving their bed or crate to a place in your home where noises can't be heard as well (like a pantry or the basement).