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To add to what Alick said, make sure your clicks are valuable. dynamyt100 is correct that your on page content might not be exactly what the searchers are looking for. You QS is determined by three things, ad relevancy as it relates to your keywords, expected click through rate, and on page relevancy. In order to improve ad relevancy, make sure you are using your keywords in your ad. If your keyword is blue widget, but your ad says buy widgets now, blue widgets will have a low QS. This also plays into your expected click through rate. If your ad relevance is below average, then your expected CTR will also be low. On page relevancy is probably the most important factor. You shouldn't advertise blue widgets and land people on a page for red gadgets. This will dramatically effect your bounce rate. Adding negatives will help improve your expected CTR also. If you have really broad terms then you could be picking up bad clicks. If you want to see where you need to improve your key terms, go into your keywords and click the bubble above the keyword status and it will tell you what is below average, above average and average. That should tell you where you need to start.