Google Website Optimizer is a free tool for creating experiments for conversion rate testing. You set up experiments for various elements on your pages and then Google randomly serves the different versions of your pages to real visitors who come to your website.
There are huge advantages to this method of testing over other sites that test your pages with people who may or may not fall into your target market. With Google Website Optimizer, you know that the people who are participating in these tests are your target market (or at least your target visitor).
Website Optimizer, Google's free multivariate testing application, helps online marketers increase visitor conversion rates and overall visitor satisfaction by continually testing different combinations of site content (text and images).
Wait for statistically significant data. As discussed earlier, initial results might reflect random chance, so wait until you have had enough traffic for the information to be significant.
Limit the elements being tested. If you create too many different combinations, it will take a great deal of time for GWO to produce meaningful results from your test.
Spend as much time developing content for a test as you would for a website. Even though this is a test, you are testing potential real options for your site. Do not get sloppy with the content just because it is a test.