I learned from my accident, where I fell and knocked out a front tooth and scraped myself up pretty bad in the process, that I need to do only one thing at a time. When I fell, my mind was in many ideas and places, and not in moving carefully.
Now, I pay total attention to the matter at hand. I try to make sure 100% of my focus is on what I'm doing at any given time. If I need to stop and think, I do just that; I stop and give my thoughts 100% of my attention.
I've found that if I slow down, pay complete attention, and don't try to do too many things at once, I get more done. I'm actually faster, and I do things better.