René Aigner's Sketchbook

[ReneAigner]

It seems to me that you have learned a huge chunk of the fundamentals for a very short period of time.

I wouldn't say that I did. You shouldn't forget that I had been drawing and painting on-and-off for nearly 10 years before I started this sketchbook (or rather my sketchbook at CA, which is older). I don't think there's a trick or an ideal "schedule" to learn the fundamnetals. The more you do (with high concentration), the faster you'll get better.
What I did learn relatively fast is complex form building (not that I mastered it of course, lots to learn there still), the stuff I talk about in my Vid. But, again, I had been drawing for almost a decade before I found Robertson's GNOMON videos.

The important thing is to love the process. If you're not having fun while you're drawing/painting, you need to ask yourself why that is. Are you not having fun because you're beating yourself up too much? Are you drawing things that you love drawing or just exercises (both are important)? And then adjust your studying habits to get the fun back into the process.

The end-all in my eyes is if you were to realize that what you really want is to "be a goood/successfull/professional artist", and you think that once you get there, you will finally have fun. I've met a few people who are like that. I don't think that can work. The learning process never ends, and you never "get there". If you're not having fun drawing now, you won't have fun after 4 years of practice, no matter how good you get.
Fall in love with the process. Draw because you want to and enjoy it, not because you want to "be successful".