Whenever I draw something; well, it's my style, but I generally render something mostly by winging it if I don't have anything to base off of (or make a 3d model of it in my head, find a good POV to render, and adapt it to a 2D medium).
If I do have something to base my drawing from, I would generally map out the key points of the picture I'm making by looking at what I'm rendering, line it up in a way of fitting the picture into the paper, stylishly, or still life. Make a sort of golden rule marker across the paper I'm using to have a proportional scale (generally as really fine, almost invisible spots on the paper; and imply the proportioning lines) I can use (especially if it's larger sketch paper or newsprint). After that, I highlight the key points of what I'm rendering (front-most points, edges, distant points, key points for comparison, as well as memory in case I get distracted, and forgot where I was last. Some mere points, others minor details I can recognize immediately), and then get cracking on refining the outline.
After that, I just about render how a picture is loaded on a computer; LODs (levels of detail). I start off with the less significant, and get a good idea of what I'm doing, then gradually refine to superior details, even to an insignificant crack, or light flare on a surface, if need be.
Of course, the majority of that kind of dedication is, like I said, for works larger than an 8.5" x 11" sheet of paper; where I can fit more detail.
On rare occasions, I do the process in reverse, or just forgo measurement and such overall; just as long as it looks right. Many a fey mood I had in art; I have made stuff sans measuring, or using a ruler for straight lines or proportioning, and have come up with some renderings that are engineeringly sound, or at least somewhat plausible.
Looking back, I am impressed with the quality I can pack in within 3-6 solid hours. Figure drawing, however, that takes some work which I, unfortunately, wasn't gifted with the talent. But some of my renderings I've done for classes are still rather well done. Then again, I consider those, along with other trinkets of note, something that helps many of my other times of drawing. For example, consider the mind like a computer, or a really complex camera. Well, my eyes photocopy what I am rendering, my brain interprets (according to boundaries and reference markers I place), and I render in the most optimal way I can.
A majority of my works were done in pencil BTW. Mechanical pencil 0.5mm to be precise. Can't go wrong with it. Larger works, of course, require more heavy-duty and more professional variety materials. Otherwise, it'll take ages to render something on a sheet that large (material also being a major factor).
I hope I helped out a bit.
EDIT:
As odd as you may look, if it's something handheld or within a human scale (1:1 scale; or a miniature non-existent model); envision it, and believe it exists. Manifest it as a private reality of sorts, and interact with it. Take note of what you have imagined, and handled, and etc.. Use your hands if you must. So what if you end up looking like a mime. You're collecting information about something that doesn't presently exist.
With notes in mind, as well as a better idea of what you want made, Now render it. The process should be much easier.
It's usually how I design my weapons and ships and such. I generally scrutinize every bit of something, like an engineer working on a groundbreaking piece of technology; or repairing a stubborn device. Weight, design, how well it interacts with it's purpose, and it's handler, etc.. All these things considered, it will significantly simplify an idea if you want/need to explain it to somebody. Plus, now you have more toys stored in your head to mess around with. Who cares if you look silly; you're having fun with it.
I guess to simplify it as best I could: Imagine like a child, render like a professional. The results, if done right, can multiply your skill development.
I already made it through Drawing II in my local college. So, I have some other pointers I can recall from the class if you need additional help.
Freebie:
Negative space. Use it well.
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Topic: Learning to sketch (aka: drawing stuff with a pencil. More or less acuratedly) (Read 1720 times)