Web Priciples

Too Many Fonts

A generally accepted design practice is to limit the number of different fonts to three or four. That doesn't mean you can't use more but be sure you have a good reason to do so. No hard and fast rule says you can't use five, six or even 20 different fonts in one document, but it may end up running off its intended audience unless the document is skillfully designed.

Small Fonts

The majority of websites are still anywhere in the range of 15–18px. We’re starting to see some sites adopt larger body text at around 20px or even greater on smaller desktop displays, but not enough in my opinion.

Low Contrast Fonts

Low contrast means a darker font on a dark background or a lighter font on a light background. The readability is impacted by such choices and it could also lead to eye strain. Usually you will want your website content to be easy to read. Nearly 9% of Americans are visually impaired.

Color

Color is often the most obvious thing about a design. Color is also capable of creating strong reactions among people, who consciously and subconsciously apply certain meanings or emotions to different colors (this is also influenced by culture, as many colors mean different things in different cultures). Color theory is an important aspect of design, and something designers should know how colors work together to create a mood or feel in a design. Sites like paletton.com and color.adobe.com can help to establish good color choices.

Value

Value describes the lightness or darkness of design elements. This relates directly to the mood a piece gives. Darker designs convey a different feeling than lighter designs. With very colorful pieces, you might not really be able to tell how high or low the value is. One trick is to convert the design to grayscale, to get a better sense of how light or dark it is. You can also look at the Photoshop histogram of an image to get an idea of where the value is more heavily concentrated.

Line Length too Long

Usability studies indicate that 50 to 60 characters per line are best, with up to 75 characters being acceptable. Long lines of text can be intimidating to read online. If the line length is too long, some people will not begin reading because it doesn't feel like a very good reading experience.

Consistency

Use similar styles for things that have similar function. Unless you are consciously intending to force people to think about your interface design, you want them to be able to quickly understand the purpose of various user interface elements. Changing the shape or colors of "back buttons," for example, is an annoying way of forcing users to adapt to your lazy designs. As with many principles of design, such a rule can be broken, but don't break it without a reason. For example, you may wish to have a call to action button with a different quality, while other buttons have a secondary style. This is okay because it reflects your desire to drive people's attention to the call to action.

Call to Action Usage

Internet marketers know that you need a good accent color to draw attention to design elements you want people to focus on. Thes are called "calls to action." If you're asking someone to "Buy Now or Start a Free Trial," you want to make sure you use a bright button color and contrast that will draw people's attention so they'll click and take the action you want them to take. The accent color should be complementary with the other colors on your website so that it doesn't clash, but don't choose a color that's already used on the site for something else.

Poor Spelling and Grammar

This reflects badly on the designer, institutions, and writers connected to a website. Copying and pasting a text into text editor and using a spell checker is a good start. There are also words like "they're" and "their" that require more subtle editing. Taking time to assure that the content of your site good grammar and spelling is a basic matter of quality control that many people will notice.