Any given visual design sits on each of these spectrums. For every spectrum, either end is valid. There aren’t any “bad to good” spectrums like “unreadable to readable”.
An interface can be all text, all graphics, or somewhere in between. Graphics includes illustrations, icons, photos, etc.
Example: If you add icons to your button labels, the interface is more graphical.
You can add more or less space between elements. You might often hear an interface described as “information dense”, but this applies to all elements in an interface.
Example: If you separate sections with dividers as well as whitespace, the interface is more dense.
An interface can have a little variety, or a lot. This is a broad spectrum that affects all sorts of properties: e.g. colour, typeface, size, and shape.
Example: If you only use one text size the interface is constrained. If you use a large title size compared to the body text, it is more varied.
An interface can have more or less apparent depth. This is often achieved with visual effects like drop-shadows. But it’s also related to how many layers your interface has, even if it’s visually flat.
Example: An interface with containers behind its content is deeper than one where the content sits directly on the background layer.
Interfaces can appear to be softer or harder. This is usually related to rounded corners and softer colour palettes. But other elements have an impact, like the typefaces chosen.
Example: An interface that only uses black and white is harder than one that uses many shades of grey.
Light and dark mode interfaces are common, but there are options between the two.
Example: A middle grey background colour is closer to dark than light.
It’s normal to design with only black and white, but colour is more common. The more colour you add to an interface, whether it’s varied colour or not, the more coloured the interface is.
Example: A monochrome interface that only uses shades of orange is coloured.
The elements of an interface can appear to be realistic, or they can be abstract. Realistic elements might imitate physical materials, but this spectrum also covers elements like cartoon illustrations and photographs.
Example: Buttons with natural drop-shadows are usually more realistic than buttons without.
Decoration or ornament is usually added towards the end of the visual design process. It includes visually interesting flourishes that are not usually necessary to make the design work. You can add more of these decorations, or keep the design as a whole plain.
Example: A website with abstract shapes dotted around the background is decorated.
The elements in your design can all align and be ordered very neatly, which suggests the structure of the page more. Or they can dance around the page and suggest that there is no structure, although usually there is.
Example: A page where elements alternate between the left and right of the page is more lively than one where they are all left-aligned.
Most designs have a structure that elements sit within. Like a grid. The design can show this structure more, or it can hide it more.
Example: A design where each container has a visible background box around its content is more visibly structured.