I came across this great illustration by Henrik Kniberg, summarizing a talk he did recently on the topic of how to create and maintain focus. The blog post is a set of short commentary, all revolving around the three points illustrated here.
Create slack. A well-known principle: if you or your team are busy 100% of the time (or even 80%), there is very little ability to focus and flex to changing circumstances. And circumstances change. The mindset that creates this much "busyness" is wrapped up in the idea of individual "efficiency" rather than flow - whether for personal projects or for those big internal projects. Any time the project is stuck means the expected value is stuck. Slack lets people move to the right thing at the right time. Kniberg talks about giving himself 2 days every week of "slack time" - what would that look like for you?
Say no. Just because someone asks for your help doesn't mean you have to agree. You can say no or not yet. Why? Because you want to focus on the work at hand and get that done first, before moving to something else. (No multitasking!)
Stop thinking, "I don't have time". Of course you don't have time if you are 100% busy. Stop doing those things which don't get you closer to the goal - which rob you of the time needed for to do your best work. I know I have plenty of those that drop to the floor when the crunch really comes.