It takes 20 minutes to concentrate and the average workplace has an interruption every three minutes. No wonder you can't get any work done.
How do you overcome this? Schedule time for your work.
Got a big webinar or presentation coming up? Got a length document to write? Need time to prepare for an upcoming meeting?
Schedule a meeting with yourself and put it on your calendar.
Got a big stack of things to do? Block a half-day or a full-day on your calendar and work from home. You'd be amazed how much work you can accomplish in a few hours of uninterrupted time.
Some may find it annoying but when I'm back from a trip I schedule my time carefully. I generally only have a day or two to run my personal errands and connect with colleagues before I'm back out on the road for another training session. So I try to schedule those days fairly carefully to optimize my time.
As they say, if you don't manage your schedule, someone else will.