I have shown a few nervous dogs, not saying it's the right way or the only way or anything but this works for me. Lots of general socialisation, always have a pocketful of treats and anyone who wants to say hello to the dog comes armed with a treat, I always encourage people to come straight in and not hesitate. Any backing off by the dog gets a light check with the lead, standing still gets no praise just be calm. Once the person has finished fussing then just a quiet praise word and move on. Get some friends the dog does not really know to practice approaching and touching the dog like a jud