A good night's sleep sets the stage for a successful day. Whether you're taking a big test, hitting the field for a championship game, or just going to your regular classes, being alert and energetic goes a long way toward doing well and getting good grades. Many things can interfere with sleep, but one very common sleep disruptor is technology. Smartphones and tablets keep teens preoccupied and in-touch with their friends and social networks 24/7. But many of those activities can upset your body's sleep-wake rhythms. From the light of a phone screen interfering with your internal clock to simply staying up too late to binge-watch your favorite show, technology can undermine your sleep in several ways. The good news is there are some great tactics to minimize this disruption without giving up important activities on your mobile devices.