Visual design principles help the UX designer to direct the user’s attention. Some parts of your design are more important than others, but those are not always the things we notice naturally. So we have to help users notice the important stuff. Below several visual design principles are discussed. The list is by no way complete, feel free to add!
Visual weight, Contrast, Depth & Size
The idea of visual weight is fairly intuitive. Some things look “heavier” than others in a layout. They draw your attention more easily. And that idea is valuable as a UX designer.
Our job is to help users notice the things that matter. And it is equally important not to distract the users from their goals.
By adding visual “weight” to certain parts of your design, you increase the chance that a user will see them and you change where their eyes will go next.
Remember: visual weight is relative. All visual principles are about comparing a design element to whatever is around it.