I have experience with sculpture so that part comes more easily to me, textures and rendering and all that stuff is pretty tough for me. I ultimately want to be well versed in all the tools so I can create my own art from start to finish. I think it's amazing that such an awesome tool like Blender is available for free.
The first tutorial I did was the Pothead tutorial and it took me over a month (and I learned a ton and it was awesome) so I decided to step back and go through the fundamentals courses. Here is my final Pothead render and the first two exercises from the modeling fundamentals course.
I like the Butterfly. Looks like some procedural texturing, or maybe geometry node work going on. Very nice!