Make sure you have a good book on force fetch and understand it thoroughly before starting. Stephen Rafe is good. Then work consistently and entirely without anger and get each step thoroughly learned before going to the next step. I liked the toe rope method best as the dog really didn't like it but it did not appear that painful. Done properly the dog ends up with confidence that he knows his job and exactly what you want from him. Strange as it seems, it tends to develop more closeness between dog and trainer. It also helps with dominance problems.