It's easy to learn one new word once you're already fluent. The same holds true for fluency in things other than languages - routines, software applications, sports, politics, just to name a few.
Think about a 30-person office where it's somebody's first day there. 29 people are fluent - they know each other's names, departments, habits, likes & dislikes. They know where the copier is, how to scan to their personal folder, and where the coffee supplies are. Today they simply have to meet the new guy - one new name to remember, and maybe something about him from the short conversation they had. Fluency +1.
But the poor new guy. He's trying to remember 29 things about 29 people, plus everything about the office. He's taking lots of notes - both mental and written, but his head's swimming with information, and the entire first week is a blur. His productivity is the lowest in the office.
There are systems, short cuts, and new things you can try in your daily life to increase your productivity. The trick is to try adding one or two at a time to the things you're already fluent in.
Try using a feature on your phone you haven't used before. Or try using a keyboard shortcut on your computer. (did you know pressing ctrl+c is the same as right-clicking with your mouse & selecting Copy? And ctrl+v is the same as Paste.)
There are thousands of ways to make things work a little faster, easier, or better. You don't have to learn them all at once - that would kill your productivity like the new guy in the office. Just learn one at a time. And once you become fluent with it, try another.