I recently presented 45 Modules in 45 Minutes: The Best Modules You're Not Using at DrupalCon Paris. Here's a tip using one of the forty-five modules in my presentation.
The Better Messages module is a quick and simple drop-in module that will instantly give your site a bit of a "wow" factor by displaying all system messages in a floating CSS popup window over your content.
You can set the window to automagically fade away after a few seconds or require that the user click to close it.
Either way, it a quick and easy way to improve the usability of your site.