@gavpartridge Thanks for the suggestions, I'll surely check out the youtube videos you mentioned and take a look at the books! Also, thanks for the last part, it gave me some hope.
@Lee-White I've never thought about this like that, thank you for your valuable advice. When it comes to the curriculum, I am currently trying that and I love it, but what I meant in the original post was finding something supplementary to that. Although it is very logically structured, sometimes I do not feel good enough to progress as quickly as it suggests.
I do not mean to say that the pace is too fast - the steps and the levels seem to be arranged perfectly. What I want to say is that I feel I need more practice when it comes to some concepts (i.e. perspective) before I move on to the next ones. With this post, I aimed to find a way to do that apart from doing the same assignments over and over again until I master them. Let me emphasize - they are not too easy nor too difficult (I mean, maybe a bit too difficult, but as you said, that's exactly the point!). I am just afraid that, although at one point I might be able to carry out the assignments well, it still may not necessarily mean I fully got the concept behind then.
Also, thanks to the curriculum I have learned how to find drawing much more fun and I just wanted to know how to draw on my own and make the most of it learning-wise.
Thank you both!