One of the biggest reasons that brands fail in their Facebook advertising efforts is that they do not split test (Loomer, 2012). They create one or two ads, find that they do not succeed and label it a failure. That is why you must try out multiple variations in order to understand what resonates with your target audience. When you realise something that does not work, stop spending money on it, when you discover something that does, keep going with it.
via Facebook Advertising: The Importance of Split Testing | Sophie Wood’s blog.