Have ID on your pet:
This is the number one most important thing!  More pets run away on July 4th than any other day of the year.  Be sure that your pet has proper identification tags with updated contact information.  On the 4th, be sure to keep your pet on a leash and keep a close eye on him when out and about.

Preparation:
The best thing to do for a dog that gets nervous, anxious, or fearful during fireworks is to properly prepare BEFORE the day arrives.

Try Lavender Oil:
Lavender is a naturally calming scent for both humans and dogs.  I have recommended lavender in the past for dogs with arthritis.  To use lavender for your dog, take some time to give your dog a massage and give some good petting.  Put just a little dab of lavender oil on your hands before massaging your dog and/or petting him in his favorite spots.  Use nice, calm, slow strokes.  Slowly massaging the outsides of the spine from the neck down is another proven approach.  Be sure not to use a lot of lavender.  A little dab will do just fine.  You do not need a lot to get the smell, and we do not want to have dogs licking excessive amounts of oil off themselves.  The point of this exercise is to associate the smell of lavender with a nice calm, relaxed state of mind.  You should do this for a few days (or more) prior to the fireworks on July 4th.  Your dog will build an association to the smell of lavender and being relaxed and calm.  Before the fireworks begin, put your dog in his “safe place” with the scent of lavender.

Have a “Safe Place” for your dog:

For many dogs the thing that makes them feel best and most safe is to be able to get as far away from the sights and sounds as possible.  Have a spot ready that your dog will enjoy and be comfortable in.  Make it somewhere far away from outside walls and windows.  This will make it easier for him to relax.  The best thing would be a kennel or crate.  Dogs generally enjoy den-like enclosures, and having your kennel or crate set up before the 4th will help them have a nice spot to go.  It is also helpful to place sheets or towels over wire crates to help block sound and lights.  Be sure to take the temperature into consideration.  It is summer and things get hot quickly.  Do not make your “safe place” uncomfortable for your dog by making it too hot.  You are most looking for a den-like area for your dog to feel safe.  If possible feed and/ or treat your dog in this area prior to the 4th.  Make sure the area is lined with a bed or comfy blankets for your pup as well.
Also remember to try and give your dog something he enjoys to help occupy him such as a chew bone or Kong filled with some yummy treats or peanut butter.

Communication & Energy:
If you will be around your dog during the fireworks, the best thing you can do for them is to remember to remain calm and feel like the fireworks are no big deal.  Dogs react to energy.  If your energy is telling your dog that you are calm and not at all worried about the sights and sounds, your dog will feel that it is okay for him to relax as well.

Exercise your Dog before Dusk:

A fantastic way to help your dog is to thoroughly exercise him before the fireworks begin.  Be sure to get your evening walk in before it starts to get dark.  The less energy your dog has, the less energy he has to put towards being fearful.  A tired dog will be more comfortable and will be able to more easily ignore the sounds and sights of the night.