The best way to get a dog to stop being scared of heights is to start by slowly introducing them to heights in a safe and controlled environment. Start by having them stand on a low surface, such as a stool, and reward them for staying there. As they become more comfortable, gradually increase the height of the surface. Make sure to reward them for staying calm and relaxed. If they become scared or uncomfortable, take a step back and try again when they are more relaxed. With patience and consistency, your dog should eventually become more comfortable with heights.