When you start designing a Web site, your options are wide open. Yet all that potential can lead to problems that may cause your Web site to fall short of your goals. The following list of design mistakes addresses the needs of commercial Web sites, but it can easily be applied to personal and hobby sites and to professional nonprofit sites as well.
This information, based on the article "10 ways to improve the design of your commercial Web site" by Chad Perrin, is also available as a PDF download.
#1: Failing to provide information that describes your Web site
Every Web site should be very clear and forthcoming about its purpose. Either include a brief descriptive blurb on the home page of your Web site or provide an About Us (or equivalent) page with a prominent and obvious link from the home page that describes your Web site and its value to the people visiting it.
It's even important to explain why some people may not find it useful, providing enough information so that they won't be confused about the Web site's purpose. It's better to send away someone uninterested in what you have to offer with a clear idea of why he or she isn't interested than to trick visitors into wasting time finding this out without your help. After all, a good experience with a Web site that is not useful is more likely to get you customers by word of mouth than a Web site that is obscure and difficult to understand.
#2: Skipping alt and title attributes
Always make use of the alt and title attributes for every XHTML tag on your Web site that supports them. This information is of critical importance for accessibility when the Web site is visited using browsers that don't support images and when more information than the main content might otherwise be needed.
The most common reason for this need is accessibility for the disabled, such as blind visitors who use screen readers to surf the Web. Just make sure you don't include too much text in the alt or title attribute -- the text should be short, clear, and to the point. You don't want to inundate your visitors with paragraph after paragraph of useless, vague information in numerous pop-up messages. The purpose of alt and title tags is, in general, to enhance accessibility.
#3: Changing URLs for archived pages
All too often, Web sites change URLs of pages when they are outdated and move off the main page into archives. This can make it extremely difficult to build up significantly good search engine placement, as links to pages of your Web site become broken. When you first create your site, do so in a manner that allows you to move content into archives without having to change the URL. Popularity on the Web is built on word of mouth, and you won't be getting any of that publicity if your page URLs change every few days.
#4: Not dating your content
In general, you must update content if you want return visitors. People come back only if there's something new to see. This content needs to be dated, so that your Web site's visitors know what is new and in what order it appeared. Even in the rare case that Web site content does not change regularly, it will almost certainly change from time to time -- if only because a page needs to be edited now and then to reflect new information.
Help your readers determine what information might be out of date by date stamping all the content on your Web site somehow, even if you only add "last modified on" fine print at the bottom of every content page. This not only helps your Web site's visitors, but it also helps you: The more readers understand that any inconsistencies between what you've said and what they read elsewhere is a result of changing information, the more likely they are to grant your words value and come back to read more.
#5: Creating busy, crowded pages
Including too much information in one location can drive visitors away. The common-sense tendency is to be as informative as possible, but you should avoid providing too much of a good thing. When excessive information is provided, readers get tired of reading it after a while and start skimming. When that gets old, they stop reading altogether.
Keep your initial points short and relevant, in bite-size chunks, with links to more in-depth information when necessary. Bulleted lists are an excellent means of breaking up information into sections that are easily digested and will not drive away visitors to your Web site. The same principles apply to lists of links -- too many links in one place becomes little more than line noise and static. Keep your lists of links short and well-organized so that readers can find exactly what they need with little effort. Visitors will find more value in your Web site when you help them find what they want and make it as easily digestible as possible.
#6: Going overboard with images
With the exception of banners and other necessary branding, decorative images should be used as little as possible. Use images to illustrate content when it is helpful to the reader, and use images when they themselves are the content you want to provide. Do not strew images over the Web site just to pretty it up or you'll find yourself driving away visitors. Populate your Web site with useful images, not decorative ones, and even those should not be too numerous. Images load slowly, get in the way of the text your readers seek, and are not visible in some browsers or with screen readers. Text, on the other hand, is universal.
#7: Implementing link indirection, interception, or redirection
Never prevent other Web sites from linking directly to your content. There are far too many major content providers who violate this rule, such as news Web sites that redirect links to specific articles so that visitors always end up at the home page. This sort of heavy-handed treatment of incoming visitors, forcing them to the home page of the Web site as if they can force visitors to be interested in the rest of the content on the site, just drives people away in frustration. When they have difficulty finding an article, your visitors may give up and go elsewhere for information. Perhaps worse, incoming links improve your search engine placement dramatically -- and by making incoming links fail to work properly, you discourage others from linking to your site. Never discourage other Web sites from linking to yours.
#8: Making new content difficult to recognize or find
In #4, we mentioned keeping content fresh and dating it accordingly. Here's another consideration: Any Web site whose content changes regularly should make the changes easily available to visitors. New content today should not end up in the same archive as material from three years ago tomorrow, especially with no way to tell the difference.
New content should stay fresh and new long enough for your readers to get some value from it. This can be aided by categorizing it, if you have a Web site whose content is updated very quickly (like Slashdot). By breaking up new items into categories, you can ensure that readers will still find relatively new material easily within specific areas of interest. Effective search functionality and good Web site organization can also help readers find information they've seen before and want to find again. Help them do that as much as possible.
#9: Displaying thumbnails that are too small to be helpful
When providing image galleries with large numbers of images, linking to them from lists of thumbnails is a common tactic. Thumbnail images are intended to give the viewer an idea of what the main image looks like, so it's important to avoid making them too small.
It's also important to produce scaled-down and/or cropped versions of your main images, rather than to use XHTML and CSS to resize the images. When images are resized using markup, the larger image size is still being sent to the client system -- to the visitor's browser. When loading a page full of thumbnails that are actually full-size images resized by markup and stylesheets, a browser uses a lot of processor and memory resources. This can lead to browser crashes and other problems or, at the very least, cause extremely slow load times. Slow load times cause Web site visitors to go elsewhere. Browser crashes are even more effective at driving visitors away.
#10: Forgoing Web page titles
Many Web designers don't set the title of their Web pages. This is obviously a mistake, if only because search engines identify your Web site by page titles in the results they display, and saving a Web page in your browser's bookmarks uses the page title for the bookmark name by default.
A less obvious mistake is the tendency of Web designers to use the same title for every page of the site. It would be far more advantageous to provide a title for every page that identifies not only the Web site, but the specific page. Of course, the title should still be short and succinct. A Web page title that is too long is almost as bad as no Web page title at all.
These considerations for Web design are important, but they're often overlooked or mishandled. A couple of minor failures can be overcome by successes in other areas, but it never pays to shoot yourself in the foot just because you have another foot to use. Enhance your Web site's chances of success by keeping these design principles in mind.