All training in image processing boils down to a story about setting a preset or how a certain photographer moved the sliders in Lightroom when processing his picture.
If you abstract away from photography as a whole object and decompose it into its components, you will find that at the heart of any photo there are two components:
The Tone Component
The color component
The main task of processing comes down to understanding the problems of tone, the problems of color, and realizing what you want to see in the end.
Experienced retouchers or photographers process the tone component first, then the color component. This reduces the risk of processing defects, the strength of their appearance, and keeps the color cleaner.
It cannot be claimed that you have to process only in this sequence. There are always exceptions. But it’s better to stick to this order of processing.
Where to start processing photos
Consider the selected photo until you understand what you want to make of it.
No need to rush to move sliders or search for the next set of one thousand and one presets for beginners.
The main point of any processing is the artistic intent, which is embodied by the processing itself.
Can’t you get it right?
Leave that shot and consider another.
As I was learning, I noticed that I couldn’t figure out how to process simple walkthrough shots.
After I realized that I wasn’t interested in them myself, I stopped wasting my time on them by eliminating processing.
Weed out the uninteresting shots. This is the second thing you have to learn.
Don’t waste your time processing pictures that are obviously boring. It is better to take pictures that are interesting and that look good after processing and retouching.