Often it looks awful showing the default design of 404 error page. Here are some points to do when designing an attractive and useful 404 error page for your site.
Tell Them That it’s OK
It’s obvious that you need to impart this message to the visitors so they will understand that the information/content they’re searching for is not available at the moment. You can say it briefly, like “Oh no! how could this happen? It’s embarrassing, don’t worry we’ll fix it soon”. Try other interesting words that you believe suit your visitors taste/style. And remember; don’t use sentences that put the blame on the visitors.
Show the Main Navigation
Yes, it’s a good idea to show the main navigation in 404 pages, so that people have more access to your contents, not just a boring link that directs them only to the homepage. Thus, your visitors exploring passion might still be channeled to other parts of your site.
Combine With Latest Content
If you believe that offering latest content to visitors is useful for them, then you should go for it! Choose the most attractive and newest content you have. It could be a featured article on your website, popular content or simply archived content. You’re free to do anything with your site, the point is you should make people feel interested and perhaps compel them to return.
Use The Site’s Theme Design
I’m certain you don’t like to have a 404 error page that appears in unformatted and plain design. By using the same theme design with your site, the 404 error page may look much more interesting, put your logo, color scheme, even cartoon characters that look amusing and many more concepts you can use to avoid making visitors feel like stranded in a desolate island.
Use The Search Box
This last point is absolutely necessary, you need to have a search box on the 404 error page. It allows visitors to do a content search, to find related topics in other parts of your site. This will make people feel more at liberty in exploring your site and you may also get additional benefits by allowing people to stay as long as possible on your site.
With these tips you can effectively make 404 error page to retain your visitors when they are unable find something relevant on your site. You should also set your site to automatically send an email each time a visitor reaches a 404 error page unintentionally.
Make Sure you check the following Links that contain Excellent 404 Page examples:
http://www.hongkiat.com/blog/60-really-cool-and-creative-error-404-pages/
http://www.smashingeeks.com/featured/15-examples-of-professional-and-creative-404-pages.html
http://10steps.sg/inspirations/artworks/60-beautiful-404-error-pages/
http://sixrevisions.com/design-showcase-inspiration/beautiful-and-useful-404-error-pages-for-inspiration/