I doubt that anybody truly knows Rust. And this is aggravated by the fact that features keep getting added. But here are two simple strategies that I found very effective in keeping us ahead of the curve.

1. Always keep the language reference with you. It's absolutely not a replacement for a good introductory textbook. But it's an unusually effective resource for anybody who has crossed that milestone. It's very effective in spontaneously uncovering new language features and in refining your understanding of the language semantics.

What we need to do with it is to refer it occasionally for even constructs that you're familiar with - for loops, for example. I wish that it was available as auto popups in code editors.

2. Use clippy, the linter. I don't have much to add here. Your code will work without it. But for some reason, clippy is an impeccable tutor into idiomatic Rust coding. And you get the advantage of the fact that it stays in sync with the latest language features. So it's yet another way to keep yourself automatically updated with the language features.