Do it completely
Put your mind completely on the task. Don't move o to the next task until you're finished. If, for some reason, you have no choice but to move on to something else, try to at least put away the unfinished task and clean up after yourself. If you prepare a sandwich, don't start eating it until you've put away the stuff you used to prepare it, wiped down the counter, and washed the dishes used for preparation. Then you're done with that task, and can focus more completely on the next task.
To make clean your view around you as to clean your mind, you can see further with concentration.