I read that one thing that you should do to increase CTR on your search ads is try to break them up into lots of customized ads in ad groups, each with only a few keywords. When someone sees an ad for exactly what they search for they are more likely to click. For example “red ink pen” should get them “Best value red ink pen, 50% off”. Not “luxury fountain pens!”.
Naturally this entails writing hundreds and hundreds of ad groups and keyword variations. But… you can automate this with a perl script or whatever you feel comfortable with. Simple make templates with tags that can be subbed out. These then get inserted into a CSV file and reimported. Both google adwords and bing support this, although for bing you have to use their windows app to import and export campaigns from csv.