Dynamic keyword insertion is a tool that allows AdWords advertisers to automate their ads with a single piece of code in the ad copy. Keywords that users are searching on are automatically populated into the ad text, making the ad more relevant, and saving you hours of work. There are many benefits to using keyword insertion, but you should also be careful to avoid ads that don't make sense or aren't converting for you.
If you decide to use dynamic keyword insertion, scrub your keyword lists of the following:
Misspelled keywords
Grammatically awkward phrases
Competitor terms
Keywords that do not make sense when inserted into your ad text
Keyword insertion should not replace proper account structure or be used with thousands of unrelated keywords all lumped into one ad group. Structure your keywords into relevant themes, and then use keyword insertion to make the ads even more relevant to every individual keyword within a well themed ad...