Contrast - Contrast is the difference between two or more elements. With contrast, a designer can create visual interest and direct the attention of the user. But imagine if all of the elements on a web page were the same in style and appearance. There would be no organization, no flow, and definitely no hierarchy. Content would be nearly impossible to digest. This makes contrast an essential part of effective web design..
Repetition - Giving the user a sense of familiarity isn’t the only good use for repetition though, it is also used to help control where the viewers eyes go and it allows you to direct them to certain aspects of the design in a way that allows you to have control over what the user does in your web site or magazine. For instance, if you have a business card with big bold company name and in the same style of big bold you have the phone number you are going to make your viewers eyes move back and forth between the company name and phone numbers giving you the two most important pieces of information that you are looking for when you are holding a business card.
One of the other major reasons for using repetition in your designs is that it adds consistency to the web page or document, in a way that brings the whole design together enough to make it seem completed. With just the right repetition an amateurish design turns into a professional design ready to be seen by the world.
Alignment - Alignment is another way of creating associations between visual elements, which help users quickly understand the relationships of objects on a page.
Alignment works by visually associating a number of elements. When you see a number of aligned elements, you instinctively believe that those elements are peers of each other, or share some other common property.
This is a really useful tool for quickly letting a user know what they’re looking at by instantly spotting relationships between different elements.
