Before choosing a dog coach, you must consider some aspects. Usually, there are a large number of training techniques there and you have to choose coaches based on which techniques you feel better for your dog training & behavior. Then you need to follow your own training technique, just like your coach after seeing complete training by them.
First, you need to think, before looking for a dog coach about how they want to train and how they have to take care of your dog. Make sure the trainer you choose must follow the same strategy. Then hang out with them and learn to train your own dog.
Make calls to several training schools and get the idea for your basic questions and you also need to ask if they use any training device to train your dog. Do you feel comfortable with the training device? And do you think your dog will respond
After getting knowledge from various trainers and training schools you have to visit those schools while they run the class and observe how dogs react to the trainers. You have to check and observe whether the dogs are happy and they look happy at the owner. If yes so it's a situation where dogs are happy with the training and are enjoying it.