Your phone would be a walking distraction machine if it were capable of walking. For the times you need to focus, the Android app ClearLock can help by blocking your most distracting apps for a set duration.
When you first use ClearLock, you'll need to choose which apps you want to block. You can then set a duration for how long you want to block those distractions. Once it's set, ClearLock will block any attempt to launch them. You won't even be able to modify ClearLock's own settings. The only way to circumvent the block is to reboot your phone entirely.
While any distraction-blocking app is only as useful as the limits of your own self-control, ClearLock helps by making it extremely difficult to get distracted. A single notification can sidetrack you, but you're unlikely to force restart your phone just because Facebook let you know that someone liked your picture.