""23 things I didn't learn in college / grad school":

#8:
Acquire, practice, and polish new skills

.

These could be related to your core work, could be tangential in your broad area, but also orthogonal, along new dimensions.

The ones with immediate value are productivity skills -- think command-line hacks and scripting languages for programmers, or LaTeX and slide-making skills for all scientists -- and tools of everyday use, whether they're classic theorems or detailed APIs.

There is another set of timeless skills that have big returns over time: examples include discrete mathematics, statistics and programming, which are fundamental skills that everyone in STEM fields -- even those outside of it -- can benefit from.

Communication skills have the biggest return on investment.

Clarity of thought is often inextricably linked to clarity of language -- not just the English language but also good mathematical formulations or clean code and APIs.

These take practice.

All three -- acquisition, practice, and polishing -- are key.

The sources you consult to acquire a skill matter.

The context in which you practice them matters.

Re-visiting, revising and polishing skills makes your thinking nimble and improves your ability to connect concepts.