Testing takes time, however, and can be expensive if not kept in check. Therefore, it's ideal to start with some proven tested known ideas and work from there.

For example, if testing has shown for decades or more that targeted advertising significantly outperforms untargeted advertising (and it does), then we can start with that assumption and go from there.

If we know based on test results that crafting an ad that speaks directly to an individual performs better than addressing the masses (again, it does), then it makes little sense to start testing with the assumption that it does not. This is common sense.

So it stands to reason that knowing some basic rules or techniques about writing effective copy is in order. Test results will always trump everything, but it's better to have a starting point before you test.

Sometimes a little tweak here or there is all that is needed to increase response rates dramatically.
When a prospect reads your ad, letter, brochure, etc., the one thing he will be wondering from the start is: ?what's in it for me??

And if your copy doesn't tell him, it'll land in the trash faster than he can read the headline or lead.

A lot of advertisers make this mistake. They focus on them as a company. How long they've been in business, who their biggest customers are, how they've spent ten years of research and millions of dollars on developing this product, blah, blah.

Actually, those points are important. But they should be expressed in a way that matters to your potential customer. Remember, once he's thrown it in the garbage, the sale is lost!