I'm a self-taught artist as the parentals wouldn't let me take art once it became elective in senior school, and the bottom line is, I learned by doing, and learned from my mistakes. The Alwyn Crawshaw books are really good, btw.
Most of what I do is motor racing based (racing cars) and working from photos, and a technique that *really* helps is called squaring up, where you use a grid to help you see what goes where. It's also good for architecture, because if one angle is out, the whole drawing is out.
You still have to draw the subject though. Mind you, most of the big names in motorsport art use a pantograph or a projector to do stuff, so what's a valid method, really?
My own style is relatively loose, I find I draw much better if I try not to reproduce photographically. Using techniques such as lost edges and just suggesting shapes and forms rather than copying slavishly have made a big difference. I did a lot of painting and drawing during the Covid lockdowns, far more so than usual, and I noticed my work improving markedly. So as with anything, practice, practice, practice. But you need to enjoy it as well, so only work when you're in the mood for it.
Here's a piece I did last summer to illustrate what I mean - a combo of ink pen and black water colour on an A5-sized piece of Bockingford.