As a freelancer, time is very valuable. The more work done in the same or less amount of time meaning the more income earned. The rest of time can be used for other purpose, for relaxing, family, etc.
There are several technique to manage your time. Check out this article from freelancefolder.com: How to get more work done in less time. The article explain about time chunking, the basic of time management called Pomodoro Technique. There are also strategy about how to manage interruptions.