A very important thing to do when working in Photoshop is to work non-destructively. That means keeping the original image data available in case you need to revert to it later.
In this video, we will learn how to perform non-destructive editing in Photoshop in several ways.
Smart Objects: https://youtu.be/pwuHGySMAkU
Clone Stamp tool: https://www.youtube.com/watch?v=xA1PcPPCsj0
Photoshop's Layer Masks: https://youtu.be/f5693hxP228
Photo Reference: https://unsplash.com/photos/ooyRHL7wVsg