There are many great reasons to teach your dog German commands. Reasons like Schutzhund competition, personal preference for the language, having a dog that responds only to your commands, and sounding more confident when you train. Whatever the reason, the German language is a wonderful, concise, confident sounding language that works well for dog training.
As your pup learns more commands his ability to learn will probably increase too. He will likely begin to generalize what he has learned and apply it to other situations better. He will also likely pick up on your communication better too. This makes training more fun, and it makes it easier to move onto harder commands. Many commands build upon one another, so it is important to start with the basics and then work your way toward more advanced commands. For example, 'down' is often taught by telling a dog to 'sit' first, and then luring the dog into the 'down' position with a treat. 'Stay' is taught after your pup already knows 'sit', 'down' or 'stand', and most tricks are combinations of simple tricks and obedience commands.
If your buddy has shown any form of aggression or is afraid of being touched, then do not use the 'Movement' method to train him. If he is afraid, work on getting him comfortable with being touched first. If he is aggressive, then work with a trainer in your area who has experience dealing with aggression, and address the issue. Aggression is best treated early.
If you are using the 'Movement' method then be gentle while you are moving your pup into the position. The goal is to gently move your pup into the position that he is learning, or to apply firm but gentle pressure to an area until he moves into the position on his own, in order to escape the sensation of the pressure. One example of this is applying pressure to the sides of the base of your pup's tailbone while you simultaneously lift up his chin, in order to encourage him to sit down.
If you would like to teach your puppy how to do something that he naturally does on his own, but will not do when you try to get him to do it most of the time, like shaking off, then the 'Catch In the Act' method will probably work best. If your pup loves treats or has a very sensitive nature, then the 'Treat' method will probably be a good fit. If your pup does not like food or will only do a behavior when he sees a treat in your hand, even after a lot of practice, then the 'Movement' method might be a great choice for him.