1. Get the busy bit done before it gets dark
Walk your dog earlier in the afternoon on firework nights, while it is still light and quiet.
Keep the evening garden trip short, on a lead if your dog is likely to bolt, and stay out with them. Check your dog's microchip details are up to date and their tag is on, in case they do bolt.
When you do head out, slow everything down at the front door. I ask owners to pause at each doorway rather than letting their dog charge out at a hundred miles an hour. Those little pauses bring the adrenaline down, so your dog sets off calmer and is better able to take in their surroundings.
2. Give them something to lick before the noise starts
This is the one I come back to more than anything. Around 30 to 60 minutes before the fireworks are likely to start, give your dog a Kong or a lick mat.
Soak their kibble and mash it to a Weetabix consistency, then pack it into the Kong in layers with a little chicken, cheese or peanut butter. I put mine in the fridge or freezer so it takes longer. The aim is at least 15 minutes of licking rather than chewing. Licking helps release calming, feel-good hormones, and 15 minutes of licking a Kong is the equivalent of a 15 minute walk around the block sniffing.
You can feed their whole dinner this way on firework nights, or scatter some of it on a towel so they have to sniff it out. Sniffing is naturally calming.