Multitasking is the craft of distracting yourself from two things you’d rather not be doing by trying to do both of them simultaneously.
Focusing is key. Concentrated focus leads to quality results.
Learn to rapidly refocus.
A martial artist can fight four opponents at one time. He does this by fighting one opponent at a time, one right after the other. He doesn't let the last (or the next) fight interfere with the present one. By focusing on the moment, his concentration defeats all.