I use my glass bow, and dragonrend it, then when it hits the ground i hit it with my ebony sword, then if it flies off again i just go super saiyan on it. Cause thats how i roll. Also you can just brign it to a populated area and have a ton of guards just start barraging it with arrows. Thats always fun too. But i like to just go super saiyan with my destruction ability that lers me actually go super saiyan with firebolt and lightning bolt. Then the dragon knows not to mess with gokufernus.