Want to know a secret? I am not always reachable. I don’t always answer my phone. Sometimes, I don’t check email all day. And I get a lot more done because of it.
When I am working on something important, I tend to shut out all outside interruptions. I go to my unreachable island of isolation so that I can get work done.
For a list of technics on how to isolate yourself read: How Being Unreachable Makes Me More Productive.