Writing a fight scene is a mainly about making sure you know what's going on, and that you're showing it in a way that makes sense.
Keep track of your stuff!
The number one thing that goes wrong in fight scenes is that authors lose track of their characters. You should avoid that at all costs. While you can certainly manage without it, I would strongly encourage that you draw a map of the area and use some kind of identifiers to show how your characters will move during the fight. This does not have to be detailed at all. For you, it sounds like you need a car, a road, and at least four people(MC, 2 werekids, 1 or more attacker(s)).
If you know where your people are, you can avoid a lot of things some people forget about.
Know your weapons
The next thing you need to know is the 'weapon' of each person in combat. I say 'weapon' because there will be people who are fighting with fists or sticks or a random rock. In your case, it sounds like you will be mostly fighting with fists and claws and jaws. All of these are melee, so most injuries will happen while two people are fighting it out at close quarters.
Because you have the werewolf aspect in this scene, you will also need a clear definement of what exactly that is, and the differences between a wolf-form and human-form werewolf. Is the human form stronger than a human, but weaker than him in wolf form? By how much? How big is your werewolf form? What wolf is it?
The more detail you have on that, the better you can make the fight scenes.
Now onto the fighty-fighty
Now that we are armed with the knowledge of what our engagers will be doing to fight, we can start to look at what they will be doing.
Your human will be throwing punches, maybe swinging around a stick or tire iron. Your kids are probably hiding in the bushes. Your attackers are probably attacking.
Do not forget your werewolves. If they are able to shift on demand, it can be a very useful move to extricate themselves from something like a choke hold or throw you off(depending on whether the shifted size is bigger or smaller). Make sure to include things like enhanced strength as a sickening crunch as you land the punch, a weakened arm by lower power, or a prosthetic leg by the lack of pain when it is kicked.
In the little details is where things get hairy and most authors make mistakes. I have gone through old fight scenes and had to rework a lot of it because I wasn't paying attention to how far I could reach or some other little detail.
Everything is possible, except for the mostly impossible
When you write each action, make sure it is possible for the character to do it. When you write
Henry dove to the ground and rolled, an arm snapping out to pick up the tire iron.
Actually get down there and try a parkour roll while trying to grab a marker. It's not easy, but if your character is a trained fictional professional, then you can handwave it and say he got it.
While in wolf form, you will have a much smaller range of motion and options. You don't have thumbs for one, so no weapons that aren't strapped to your paws. And those probably won't work very well. You will be limited to biting, clawing, and probably charging. A human will have a lot of maneuverability. This does not mean wolves are only useful for charging, they are very fast and strong animals.
In a fight against human form werewolves, a wolf would most likely be used to:
- chase fleeing hoomans
- intimidate
- doing what police doggos do in a fight, which is pretty scary if your the guy in the padded suit. Also severely limits movement, damages a limb, and distracts the target at the same time.
Rule of Cool
If it is not used elsewhere in the book, fight scenes are the number one place where you can get away with Rule of Cool. Yes, it is impractical to jump into the open with a pair of pistols and slide across a floor coated with machinery lubricant, but it's super awesome when you kill the two dozen mooks while bullets and explosions are flying around you. (There's a scene of this in Leverage but I can't find a clip of it on youtube. Will link when I find it.)
TL;DR
A fight scene is all about orchestrated movements. When they line up perfectly, you have a beautiful flowing scene. When they don't, things feel choppy and off-balance. Keep track of everything, and you will be able to have a very pretty scene.