Dogs snore for the same reasons that people snore--because their airways are somehow obstructed. This could be due to sleeping in a strange position, from a facial deformity, from being overweight or from having a health problem that has narrowed the dog's airways. Curing a dog of snoring requires short- and long-term solutions.
If the snoring dog has a short nose (brachycephalic), then they already have a hard time getting enough air to breathe. They will always snore to some extent. These breeds include Pekingese, pug, Boston terrier, boxer, Shih-tzu, Shar-pei and all bulldog breeds. If possible, have the dog sleep in another room if the snoring is really bothersome. Be sure to take to the dog to the vet if the snoring gets worse or additional noises are added to the snoring such as wheezing or rattling.
Short Term Solutions
Waking the snorer up and having them shift position is a temporary solution for human and canine snorers. But when a dog sleeps curled up, then the dog snores less then when they are laying flat out. Changing a dog's bed to a round bed may work to lessen some snoring. Propping the dog's head up with an extra pillow may also give enough of a change of position to stop snoring. If the dog is congested, the use of a humidifier can help open up narrowed airways.
Long Term Solutions
If the dog is congested or suffers from allergies, then the dog needs to be under veterinary care. If you do have a dog with breathing difficulties, do not smoke around the dog and keep the dog from tobacco smoke as much as possible--the smoke will irritate the airways. If the dog is overweight, then all of the extra flesh is pressing down on the dog's throat, blocking airways. The overweight dog will not only be more prone to snoring, but also to far more serious health concerns such as heart disease, arthritis and diabetes. Work with your vet to determine your dog's ideal weight and new diet. If the dog will swim, incorporate swimming into the dog's exercise routine, as this is a great way for the dog to burn calories without putting strain on the joints.