One of the challenges starting out is that you don't know what tool might help with what you are working on. The program is so vast, it's hard to know what tools are most worth learning for photographers, which ones are more for graphic designers, etc.
It's also hard when you are starting out to sift the better videos from the vast options.
For me, photoshop is for when I need to use layers and/or complex masking. I try to do everything I can in Lightroom.
If you are lucky, your local Community College (what we call them in the US, not sure what the generic international name would be) might have a good program. If so, this is ideal because you will get an overview, feedback on your work and direct suggestions.
I have found Lynda.com helpful for a methodical approach, if you don't have a good local training option.
My best advice today to my earlier self starting out with photoshop: start by mastering the curves. A most versatile tool.