One of my favorite reports to run in Google AdWords to optimize campaign performance is the Search Query Report. You can run this report by clicking “See search terms” in the Keywords tab in your account. The Search Query Report shows you the actual keyword terms and phrases that users searched for when your Pay-Per-Click (PPC) ad shows an impression on the search engine results page (SERP).
From this report you can see which keywords have brought in the most conversions and even the cost per conversion. It would be best to pause any keywords that have a high cost per conversion and low ROI. Also, if you find that there are search terms which are bringing in conversions, but are not currently in your campaign, you should add these terms to your campaign. This will increase the quality score of your ad and therefore decrease the cost per click (CPC) of the keyword.
On the other hand, if you find search terms that are not relevant to your campaigns, you should add these terms to your negative keyword list. Doing so will increase your click-through rate (CTR) because your ads will receive more clicks without wasted impressions, thus decreasing your CPC as well.
Another way to use the Search Query Report is to check the match type you’re currently using for exiting keywords. Also, you can create more tightly knit ad groups based on common groups of search queries. The Search Query Report is an excellent tool to help optimize your paid search keyword menu and lower your average CPCs for your campaigns.