The teacher told me to think of my glasses as “a box around your head.” In other words, if they have no perspective, and aren’t bigger than my head, then I’m doing it wrong.
So anyway, today I practiced drawing my glasses by themselves, and as you can see from my construction lines, I literally started out with a box and went from there. Better, no?
What I’m really starting to understand about drawing, and why it’s so difficult, is that you constantly need to switch between two modes: seeing and constructing. By that, I mean you have to be able to draw exactly what you see, getting the angles and contours right. But you also have to understand the internal structure of what you’re drawing–otherwise you might draw one perfect shoulder at a time, but find that one of them’s dislocated when you step back and look at the entire figure.
Conversely, if you spend all your time concentrating on structure, you’ll find that the likeness is off, and you’re drawing mostly from your head instead of what’s in front of you.
I’m sure with enough practice, this juggling act will become more transparent, but for now, it takes more concentration than I’ve mustered up in a long, long time.