The truth is, the very best ads work because of the strategy behind them.
Think about it this way, if you've prepared a delicious meal and your dinner guests are hungry, they probably won’t care what kind of plates you serve the meal on. Put another way, if your message and offer appeals to the people you're writing to, it barely matters how you present it.
Of course, there are things you can do to make your ad clearer, more direct and more interesting, but these are definitely secondary concerns. If your strategy is wrong, the best penmanship combined with the best graphic design in the world won't save you.
Imagine trying to encourage teenagers to invest $200 a week for their retirement. On the surface, it sounds like a reasonable idea, but realistically, you'd be lucky to get a single interested adolescent. The strategy is completely wrong. First, you're going after the wrong group of people and second, the amount you're asking for probably exceeds their weekly income.
That's an extreme example, but a good one to highlight the problem with most advertising - it's saying the wrong thing to the wrong people, or, even worse, saying nothing to anyone at all.
If you've been writing the kind of ads that just say “hi there, my business name is x, and my phone number is y”, then you shouldn't be surprised if your ads haven't led to the success you want.
Those ads rarely do anything but fund a newspaper or magazine. People will NOT read generic ads like that, which is why you have to promise to give them something.
Behind all of this is a strategy. So let's define the word “strategy” - it means a plan, what you want people to do and how you're going to get them to do it.