I found that one of my biggest time wasters was flitting from one thing to the next and hardly ever finishing a particular task, so at the end of the day I was left with many half tasks done.
My best advice would be to finish 1 task before starting another one.
Even if it means closing down your emails for the duration in order to prevent interruptions.
IM, skype is another tool that can become a time waster in some instances.