https://humanwhocodes.com/blog/2014/01/07/how-to-be-a-mentor...
I think this is critical, and engineers seem to struggle with it more than the average person. Remember your codebase is a business tool, not an art project. It's okay if some of your junior person's inelegant code ships as long as it works acceptably well. If you try to make every line exactly what you would have written, you'll drive yourself crazy.
Some mentees will also likely have a desire to impress you so they'll get good at doing things exactly how you want them to do it. This is also learning, but not the learning you want.