I suggest that the best way to keep from going bonkers is to … no, I won’t say “start small,” but rather, “start incrementally.”
If you try to create a perfect model of a VW your first time out of the block (or your second, or your third, or your forty-fifth, or your forty-sixth…), hey, let’s face it, you’re not gonna get “there.”
But … you certainly will get “somewhere,” and what you really want to concentrate on is figuring out – self-critiquing – just where that “somewhere” is, and isn’t. Your eye’s gonna love some things, instinctively, and reject other things, again instinctively. Pay close attention to what your well-trained eyes are telling you, “instinctively,” and try your best to put those instincts into words.
Nevertheless, don’t judge. Observe. Compare to reference photos. Keep every iteration of your work-in-progress and compare one to the other. Don’t let yourself get discouraged. Rome was not built in a day. If you set unrealistic expectations, then: (gasp!) “you’ll fall short! Imagine that!”
Take what you did do, then consider how you might make it a little better, and (with a copy of what you’ve got), incrementally try to improve upon it a little bit. Then observe. Next, with a copy of either that file or its predecessor, experiment again. Keep a diary.