A young, energetic dog can be a handful. They bark, chew, jump, and do other annoying things. So use that energy to your advantage. Walks, time at the dog park, games of tug or fetch - these all help to tire out your pooch. Also, don't forget that training is mentally stimulating (and tiring). A tired dog is a good dog!
Jeff Dentler, CPDT-KA, IAABC-ADT, FFCP, CTDI