OK. So you've written your sales letter and put it up on the web. Or it could be that you've done your testing the traditional way and physically mailed it to your list.

The results have come in and they're kind of OK. But nothing to write home about.

What happens next? Should you knock the project on the head? Run with it? Or you could tear your copy apart and rewrite some or all of it to improve your response?

The best answer is that you should improve your copy. Which is where split testing comes in. If you don't split test your results, you won't know whether your changes have made any difference at all.

In traditional mail order, you'd split your list in two (hence the name split testing). 50% of your list would get version one and the other half of your list would get the second test. Being sure to only change one thing at a time, otherwise you won't know which "thing" worked or didn't work.

The headline should be the first thing you test. It's impossible to know whether your headline is a world beater until you've pitched it against a different one. Keep testing and testing.

The internet allows you to test things like your headline very quickly and simply. Upload two different copies of your sales pitch (probably called something imaginative like index1 and index2). Then measure which gets more orders over time.

As soon as you've determined the best version, repeat the process and test again. Either by testing a different headline or maybe a differnt variable entirely. Maybe your guarantee policy. Remember to test your headline color. Possibly the price tag you've put on your product. And remember to test a higher as well as a lower price. Sometimes higher prices get the same - or even more - orders, or they may just earn you more money.

One way to speed up the testing is to use specialist testing software. Software will allow you to test a number of variables at once. It will then use some complicated math to rapidly decide which is the best version of your split test. (You don't need to know about the calculations the software runs). You can find this split testing software here.