This activity will allow your dog to make great use of their sense of smell; get a hold of tennis ball, stick, or dog toy and then mark it or attach some sort of item to it that will cause the ball, stick, or toy to emit a strong aroma that your dog can follow with their nose. Try scenting the object you plan on having your dog fetch with a pleasant smell, like that of their favorite foods.
Your dog's senses of smell and hearing will really come into play with this activity; find a large clearing without any hazards to your dog, then try hiding away from your dog. Your pup will sniff you at their own pace, but be sure to adjust the difficulty to meet your dog's proficiency at this activity.
A gentle, friendly game of Tug Of War is another excellent activity to try out with your dog; get your hands on a dog friendly rope and offer the other end of it to your dog. Once you both are ready, lightly and playfully tug on the rope with your dog. Be sure to let them win a few rounds to build up their confidence as well!