Focus is nice, but it'll only get you so far. Much more useful is prioritizing your work, and avoiding unnecessary work.
Focusing on bad implementation: a waste of time.
Focusing on bad solution: a waste of time.
Focusing on solving wrong problem: a waste of time.
Choosing the right problem, the right solution, and not wasting time during implementation (e.g. by spinning wheels without asking for help) will give you order of magnitude improvement. Focus will get you smaller improvements, though it is useful.
Focusing on bad implementation: a waste of time.
Focusing on bad solution: a waste of time.
Focusing on solving wrong problem: a waste of time.
Choosing the right problem, the right solution, and not wasting time during implementation (e.g. by spinning wheels without asking for help) will give you order of magnitude improvement. Focus will get you smaller improvements, though it is useful.
More here on what it takes to be productive here: https://codewithoutrules.com/2017/10/04/technical-skills-pro...
(And my personal take on staying focused, which is a lot more about goals and less about distractions: https://codewithoutrules.com/2017/08/03/stay-focused/)