Saying No
There are infinite things to learn, goals to achieve, places to visit, books to read, and people to talk to.
Scarcity is not the problem, abundance is the problem. This is why focus is important. Focusing means to gain clarity on what you want, commit to it, and say no to everything else.
Saying no is one of the biggest levers we have. This is how to protect our time. But like many things, its easier said then done.