The idea behind a piece can be just as important as the technical execution. The ideas don't need to be deep, maybe you just want to make something pretty or cool. Even in those cases, the concept behind the artwork plays a part in how the artwork is perceived.
Vision is just the interpretation of light from a thing being viewed entering an eye or camera. When we make images, we're making things that, when viewed, get interpreted as a vision of what we want to depict.
Though our artwork might depict objects with volume, environments with depth, or lively renderings, ultimately they're just flat images. We can conceptualize and visualize the depth and behavior of light within a piece, but in practice we're just making shapes, lines, and edges on the canvas or page. These shapes, lines, and edges create the illusion of what we imagine.
A shape is a mass of similar colors. Certain aspects of a shape can produce different impressions. A shape doesn't have to be a continuous mass of color. A cluster of shapes of similar color can be perceived both as the individual shapes and the area of the whole cluster. For example, rounder shapes can give a friendly or calm impression. Sharp, pointy shapes can give a energetic or dangerous impression. Right angles are very rigid and stable.
A line or stroke can be thought of as a very thin, often long shape. Again, how sharply angled or curved and smooth a line is impacts the kind of impression the line creates. A lot of simple drawings are made entirely of lines. It should be easy to see that lines can compose the bounds of more shapes.
Thinner lines tend to appear lighter in value, lower in contrast, and further away. Thicker lines tend to grab more attention, and so might look closer. This is heavily influenced by context. Shape overlap and perspective can easily change the depth. A lot of little lines and shapes can make more contrast than a couple of thick lines.
An edge is a boundary between shapes. This is not same as a line because an edge isn't necessarily always its own shape. Although, in a drawing made only of lines, we might use lines to create the impression of an edge. A hard edge is a sharp boundary where one color immediately meets another. A soft edge is when boundary is more gradual, such as with a gradient or dithering. A lost edge is when boundary is essentially non-existent. This happens when an edge is hinted at, and the brain fills in the gap.
If you draw a dog with 2 legs and a head twice the size of its body, it will never look quite right. If you know how to draw a cat, it gives you a better idea of how to draw a dog.
Go look at stuff.