From a usability perspective, the design of your site’s web pages has to be easy for users to follow. One common rule we follow is the ‘7-second rule,’ meaning your visitor has to be able to figure out what you’re about and what you offer in 7 seconds or less.

But once you’ve grabbed their attention, you’ve got to keep them there.

Bad site design from a usability perspective will certainly kill your site’s good will. How many websites didn’t have easy to follow navigation or otherwise made it difficult to find what you needed?

Sadly, this is more common than anyone wants to admit.

Below is a list of the 10 most common web design mistakes compiled by usability expert Jakob Nielsen. Of course, there are other design issues from an SEO perspective you need to consider. But these following 10 mistakes will kill the experience for your visitors, which will depress the number of visits and conversions you ultimately receive.

#1 Most Common Web Design Mistake – Bad Search

When site visitors can’t find what they’re looking for through the site’s navigation, they turn to search. Some just jump right to the search bar and type in their query. However, many online users don’t have a keen sense of grammar and spelling. If your site’s search functions are overly literal, this could hurt you.

Be sure your search functions are able to handle typos, plurals, hyphens and other variations of important terms on your site’s materials.

#2 Most Common Web Design Mistake – Over-use of PDF Files

Adobe PDF files are generally reserved for extensive e-books and other information that’s better off being printed. If a user encounters a PDF while browsing, it breaks their flow and leads to a bit of frustration. Also, layouts for these documents aren’t meant for the web and usually display in very small fonts that are difficult for users to handle on-screen.

Therefore, only use PDF for manuals, e-books and other large chunks of content that need to be printed. Convert any information that should be browsed or read on-screen into a real webpage.

#3 Most Common Web Design Mistake – Not Changing the Color of Visited Links

Understanding where you’ve been helps you better understand where you’re going, both in life and on websites. For the web, links are the key component in this navigation process. Knowing which links you’ve already visited keeps you from unintentionally revisiting the same page again. Testing has shown if sites do not change the color of a link once it’s been clicked, much disorientation and frustration among users will result.

Therefore, be sure you setup your links to change color once the visitor has clicked on it. This will help your visitors avoid visiting the same page twice, or three times.

#4 Most Common Web Design Mistake – Non-Scannable Text

A big mistake among web copywriters and designers – not having copy that’s scannable makes it look intimidating to readers. Boring and painful are other metaphors that can describe one’s feeling when they run into non-scannable text.

Use bullet points, sub-headings, bold-print, short paragraphs and a simple writing style to make your copy more inviting. Remember, most users scan, they don’t actually read everything word for word.

#5 Most Common Web Design Mistake – Fixed Font Size

Web design platforms like CSS (Cascading-Style Sheets) provide an option to allow you to disable a web browser’s change font function(s). The default most of the time, 95% of the time in fact, sets the font-size kind of small, reducing readability. This can be especially frustrating for users over 40 or with poor eye sight.

Respect users’ choice and allow them to easily resize the font to a level needed for them…to make it easier, express font-size in relative terms rather than pixel size.

#6 Most Common Web Design Mistake – Page Titles with Low Search Engine Visibility

Your site’s <title> tag is a very important element of your website. It’s what search engines will display in your site’s listing, which is what users first see about your business and will click on if they’re searching on Google or Bing. It’s also the default setting if users bookmark your site. Many sites though say ‘Welcome to’ or begin their <title> tag with ‘the.’ Also, many sites don’t have different <title> tags for each page.

For your homepage, begin your <title> tag with your company’s name followed by a brief, keyword-rich description of what you do. Search engines though only display the first 66 characters but you can have a few more if you need them. For other pages’<title> tag, include important details of the page’s content using keywords you’re targeting.

#7 Most Common Web Design Mistake – Advertisements (…or things that appear as one)

As the web has developed, users have become quite keen on avoiding anything that looks like an advertisement – or anything that interrupts their ‘goal-driven navigation’ as stated by Nielsen. Text-ads in search results are an exception to this rule of course. Unfortunately, many good design elements have similarities to ads and get ignored as well.

It’s therefore best to avoid any design elements that look like advertisements. Banners, pop-ups and overly aggressive animations can all potentially pose frustrations for users. If you have them, it’s more likely they’ll be ignored. Pop-ups in particular may in fact draw scorn from users.

#8 Most Common Web Design Mistake – Violating Design Conventions

One of Jakob Nielsen’s laws of usability – “users spend most of their time on other sites”

Meaning, users have certain expectations already set before they reach your site, which are formed by their experiences on other sites. Consistency is therefore an important principle – when users know what to expect, they feel in control. When expectations are broken, many will feel insecure and leave your site.

Stick with common design conventions in order to maintain consistency with what’s commonly done on most other sites. You can of course, and should, make yours unique from your competitors. But with certain navigation and design elements, you want to maintain some form of consistency.

#9 Most Common Web Design Mistake – Opening New Browser Windows

If you’re like me, having a new window or ‘pop-up’ just come up on the screen can be frustrating as all get out. Considering systems can freeze up, loading a user’s machine with more ‘junk’ can in fact lead to a lot bad feelings. Besides adding pressure on their systems, new browser windows disable the ‘back’ button, which is what a vast majority of users use to navigate away from a page.

Links should therefore only replace the current page with new content. If a user wants to open the page in a new window, they can easily do so by right-clicking on their mouse.

#10 Most Common Web Design Mistake – Not Answering Questions

Since web users are inherently ‘goal-driven,’ not answering important questions about your products or services is a big failing of many websites. Not providing any specifics or burying them deep beneath a bunch marketing jargon will make users think what you offer can’t help them. One of the best examples of this is price – how much does it cost?

Ecommerce sites generally don’t make this mistake but a lot of B2B sites do unfortunately. But many B2C ecommerce sites too may leave the price out of lists like category pages or search results, which can lead to user frustration and reduced conversions.

One principle we always like to remember and urge you to think about – “people buy things from people, not websites.” Therefore, their experience must be enjoyable and not rife with uncertainty and errors. It should move along flawlessly – each flaw reduces good will and ultimately conversions.