The Portrait Masters - The Retouching Guide
https://theportraitmasters.com/product/bonus-gift-the-retouching-guide/
In this gorgeous 8 page PDF guide, Pratik dives deep into his process and workflow when retouching. He discusses commonly used tools like the clone brush, healing brush, liquify, and many more.  He makes his recommendations on when and how to use them. He even shows you the keyboard shortcuts for each!