2. If you feed dry kibble you can scatter/hide them all over the house for your dog to find, you can also break delicious treats up and use them too
3. Consider crate training your dog, crates are a saviour to many problems and once a dog learns that it is their safe place they really love them.
4. If they chew things they shouldn't, consider using Bitter Apple, a product with a bitter taste found in pet stores to deter dogs from chewing.
5. Perhaps they need more exercise or more physically demanding exercise, try adding a doggy back pack on walks, going for jogs or faster paced walks (great for your health too!), playing fetch or catch.