When it comes to Google Website Optimizer, the more traffic you have, the quicker you can test out the different options. Depending on the traffic to the testing page, you may be able to start making conversion decisions in a few hours. But, don't worry if it takes you several days or weeks of testing to see an obvious pattern. I like to allow at least 100 visitors to see each variation before I make a decision. More if the site is high traffic.

Don't overlook another great feature of the module—A/B testing. A/B testing is similar except that it allows you to test completely different versions of a Drupal page. Imagine that users click on the contact us link and half see a long form and the other half a short form. Which gets more visitors to fill it out? Don’t guess, run the experiment.

Regardless of how many tests you run, utilizing multivariate and A/B testing on your site can help you improve your conversion rate on an ongoing basis. Stop guessing, and start testing your design elements. The stats don't lie—you just have to start collecting them.