The idea that one should think about the enhancements, etc. outside of the context of the toolset is sound advice, in the sense that one should be able to identify what exactly their vision for the image is before they go about attempting to produce the result.
That said, there are straightforward image processing tools and workflows within Photoshop that are routine and knowing that you may want to apply these to some, most or all of your images as a matter of refining the original result can be more efficient if you have a specific source of information that covers precisely this topic. I have found over the years that the work by Martin Evening exemplifies this efficient, detailed coverage and instruction.
See, for example:
Adobe Photoshop CC for Photographers 2018
by Martin Evening
https://www.amazon.com …phers-2018/dp/1138086762/
- you could probably even get away with the earlier CC versions in used copies for less $$$.
This series of books (I think the first version I purchased was for CS4, or maybe earlier) has been an evolving and refined explanation of how a photographer might go about using Photoshop for their image making. You can read it front to back, or hop around the various topics - however you choose to use it, Evening lays out the "why" and then demonstrates the "how" with various Photoshop tools.
Another point to consider when investing time and effort and money in the process, is the image worth it? Is there something compelling about the squirrel image that makes the effort to transform it into your vision worth it? Answering this question honestly will 1) make you think about what exactly it is you would potentially want to do in Photoshop, and 2) save you a lot of time and effort if the ultimate answer is an honest, "nope, this image isn't really worth it."
kirk