1. Disabling the back button. 

Evil site authors long ago figured out how to break a browser’s back button so that when a user pushes it, one of several undesired things happen: There’s an immediate redirect to an unwanted location, the browser stays put because the “back” button has been deactivated, or a new window pops up and overtakes the screen. Our advice: Never do it. All that’s accomplished is that viewers get annoyed and do not return to your site.

2. Opening new windows. 

Once upon a time, using multiple new frames to display content as a user clicked through a site was cool–a new thing in web design. Now it only annoys viewers because it ties up system resources, slows computer response and generally complicates a visitor’s experience. Sure, it’s easy to use this tool. But don’t. With tabbed browsing common in browsers like Firefox, users who wish to open links in new tabs can do so if they wish.

3. Failing to put a phone number and address in several easy-to-find locations. 

 If you’re selling, you need to offer viewers multiple ways to contact you. The smartest route is to put up a “Contact Us” link that leads to complete info–mailing address, phone and email address. That link should be on each and every page of your website. Even if nobody ever calls, the very presence of this information adds real-world legitimacy and transparency to your site and comforts some viewers.

4. Broken links.

Bad links–hyperlinks that do nothing when clicked or lead to “404” error pages–are the bane of any web surfer. Test your site–and do it weekly–to ensure that all links work as promised. Include a “Contact the Webmaster” link in your site’s footer so users can quickly let you know if they find a broken link or other mistake on your site–and fix those errors immediately.

5. Slow server times.

Slow load times are inexcusable with professional sites — it’s an invitation to the visitor to click away. What’s slow? A recent study by Akamai Technologies, commissioned through Jupiter Research, showed that online shoppers, on average, will wait only four seconds for a site to load before clicking away. If your site is loading significantly slower than this, put it on a diet–images may be too large or special add-ons, like a Flash introduction, may be slowing things down.