As you can see, knowing your customers can play a large part in the success or failure of your advertising. The better you know them the easier it is to find the message that works and the fewer tests you'll have to do. You can test too much and that's what you'll want to avoid. The purpose of testing is to do as few as possible and lean from the results to make the testing pay off in the long run with profitable advertising. Here are some testing guidelines to keep in mind when you design your test packages.
Testing can be an ongoing process.
That's a form of testing that never ends. Don't try to test everything at once. It's too hard to keep track against the control group. Find one item that you really think would make a difference to your customers and just test that. If you are using direct mail to test you need about 100 responses for the test to really give you a good example.