Alright well.. I've been doing a ton of reading over the past few weeks, so I'll try and summarize stuff that's been posted elsewhere in this thread. If anyone with actual knowledge and experience corrects me, heed their wisdom!
Also it's late, so... I blame that if my brain is muddled.
Anyone have tips on perspective in that context?
I'm guessing by how you said it that you're referring to the viewing angle of a piece with respect to the point of view of the "camera" that the picture is drawn from, i.e. the perspective viewpoint of the illustrator. "Perspective" in art refers to how figures in a piece relate to the horizon of a picture, and pictures come in one- two- and three-point perspectives. I know a bit about why that etching is wrong, but I'll get there in a minute.
For drawing things w/o a subject... well that's fine. Everything, at its core, is just a series of simple shapes that combine to make a larger one. Human bodies all have the same basic ratios, and you can get pretty close consistently with a little practice.
(From the Loomis book linked earlier)
Imagine a ball with two lines that intersect at a right angle in the middle, forming a +. The vertical line bisects the nose, with the eyes on each side (and about an eye's width between the eyes). The top of the ears join the side of the head at the horizontal line, about halfway around the ball. Under that there's a bit-larger-than-head ribcage, the spine, hips. Elbows fall at about the ribcage and your hands fall around where your pockets are (the hips). Legs are about torso-length with knees in the middle and feet at the end. If you follow something about like that you'll be pretty close, and working from the top down is by far the easiest (or only) way to construct a body.
Here's some examples of the head proportions I did for Loomis practice (you can see my guide lines not-fully-erased, especially in the first one), and a re-link of the skeletal frame I sketched for the Lorraine pic earlier:
And a badly proportioned picture I made in MS Paint. Take a look and see where I went wrong:
The torso is way too big, and everything else is roughly proportionate. If I had been paying better attention, I would have shrunk it before I moved on, but I kept drawing and made everything else out of proportion to the head. Also... shoulders do not work that way.
* * *
That etching is awesome, and it's not shading that's the issue. Take a closer look at where your brain tells you things logically must be, and where the picture tries to tell you they are. As objects move away from you they appear to get smaller, and they farther they are the smaller they get.
Start with the foreground man with the fishing pole. He's fishing in the same water that the guy sitting on the bank is... but there is a building between them. To reach that far, the foreground man's fishing pole would have to be taller than he is or longer than the building is wide, at minimum, to reach that far.
The near swan in the lake is the same approximate size as the bull next to it. The man in the boat is about as far away as those dog-sized horses drawing the miniature cart over the bridge. My favorite is the fellow smoking a pipe on the far hill; he's the same size as the person leaning out the window... which from that far makes him as tall as the oak tree he's standing near. The sign on the building is blatantly impossible, and the roofs imply that there are two buildings oppositely sloped on different sides of a very steep valley that can't be the one the swan and fish are in. There's more, as well.