A very common error with pay per click is not tracking the results, traffice and visitor numbers. As all your adverts cost money for every click, you need to know where the traffic is coming from and what the conversion rate is. Each site has it's own indvidual results and you need to tailor your campaign to make the most of the best results. This is why tracking is vital.

Another big mistake is sending visitors to outdated sites or even worse, broken links. Sending visitors to a specific landing page which is relevant to what they are looking for has been proven to increase sales. These customers are then likely to return and recommend you to others.

So, the advice here is, always check your data and keep checking that links work.