I've been trying out blender, following along with the donut tutorial, but it feels like I am just copying and not learning much. I often get sidetracked and try to make something a bit different to the tutorial but its just so difficult and never works..
For example, I wanted to create a donut, but with no middle (like the donuts with filling inside). I spent so long trying to make the initial mesh and when I got something that looked correct, viewing it with textures showed a completely broken, and stretched out in places image.
Any ideas for getting over this learning curve? Is it just watching YouTube tutorials and following along until I randomly discover new info to use in other projects?
For me it was sheer stubbornness that got me through. Realistically, it's important to know that a model is made up of a series of very different kinds of tasks. When I was learning, I focused on only one of those tasks at a time. For instance, I would just sculpt for a while and became familiar with those tools. Then, when I felt I had a good handle on that, I asked "What's next?"
Sculpting, Hard surface modeling, retopology, UV unwrapping, texturing, shaders, rigging, renders... Pick one thing and forget the rest for the time being. It becomes a lot easier to handle and learn when you're looking at Blender with blinders on. You can't really get around using tutorials because learning this software is like climbing a vertical wall for someone that hasn't used modeling software before. But it can be a lot easier finding tutorials and answers you need when your scope is narrowed down to doing one specific thing at a time.
So, figure out the steps for whatever pipeline you're interested in. Then break those steps down and work to understand them one at a time.
Pick one thing and forget the rest for the time being
This helped me out a lot. As I wrote before: I wanted to create low poly models. Not having much success with that, I ended up trying sculpting and loving it. Now I have my own MyMiniFactory store and patreon.
I'm the exact same as you and I don't really enjoy plainly following tutorials. What might work for you is to keep doing what you're doing, and let that shape your growth.
Using your experience with the donut tutorial as an example, you went through the effort of doing something different, but all your textures are stretched out. You might ask a beginner 3d/blender community why, and they might tell you about how uv mapping and texturing works. You can take that information and follow up by watching a tutorial on texturing.
3d art is definitely hard to get into, and the biggest challenge when growing your skill is keeping your motivation and practicing as frequently as possible. Every issue you can see with your models is an opportunity to grow, and you can become amazing if you keep it up!
So tutorials are the equivalent to classes, except you get to choose the content that interest you. Following tutorials seems bland and dumb, as obviously you don't want to model a donut, or a teddy bear, or any other gimmicky shit, however it introduces you to the tools of the program and teaches you how they function, how to use them, and the little hidden bells and whistles within each function.
It's kind like, you don't know what you don't know. How can you learn which tools you need to achieve your goal if you've never actually used them before. Tutorials show you that, step by step.
The only other ways to learn are getting a book that gives you structured tutorials, finding a good video set (such as someone from YouTube), or self-learning through interaction with the software...so not really sure what sort of answer you're looking for.