Staying focussed is not always the easiest thing to do. There are so many distractions ranging from the environment you are in to what technology you use.
To me staying focused is a state of mind. Being able to drown out the noise and just tune into what is important at a given time.
One of the biggest reasons I love cubing so much is that you are forced into this state of focus. When you take cubing beyond just learning how to solve one - you get to experience a level of focus that is very hard to articulate.
I feel by spending time in this focused state while cubing, my brain is now much better at keeping distractions at bay.