There is no doubting the success of Google's Adsense program. Even Yahoo! and Kanoodle have joined in on the game, offering to join publishers with advertisers. Given the right circumstances, its a win / win situation for both.
There have been many sites that promote Top Paying Keywords and how if you add these keywords you can instantly improve your Adsense revenue. However, if you really want to see a dramatic increase in pay per clicks, you need to ensure 2 very important areas are addressed. They seem very obvious, but many site owners miss the opportunity to attract higher paying ads simply because they ignore these two areas.
Optimization
Many "would be" web designers decide to build a site around the highest paying keywords, yet, forget to optimize their site around a specific keyword. Instead, they forget the basics of how to properly create a title tag, page description, keyword density and having clean search engine spider friendly code.
Remember, its the source code that the Adsense and Kanoodle programs are using to decide what ads will appear. If your top 2 keywords are "insurance" and "downloads", you may find that you end up with ads regarding "insurance downloads" which of course will not pay much.
Also, having a high keyword density score for the keyword can get you into trouble with the search engines (specifically Google). Keywords spamming is never a good idea. Optimize your page and you will search more hits to that page and not confuse the bots that create the ads for you.
Content
This is by far the most important and most missed tips. If you are going to include top paying keywords on your site, remember, if you want to attract high paying ads, you need to be selling your visitor on what your advertiser wants. Your content should sell to the visitors needs. Why should your visitor consider car insurance? What are the benefits of car insurance? Where can they get the best quotes? If you pique the interest of your visitor, they are more likely to click on your ads than if they feel that they are not getting the information they came to your site for in the first place.
Your content should have a specific flow to it. If you start jamming keywords into your content, your visitor will automatically suspect that you are trying to deceive them. Once you do that, they are gone! Why waste your visitors time after working so hard to get them to your site in the first place?
Well optimized, focused content will always produce better, higher paying ads. That is why you are a publisher: you want those high paying ads on your site. What use though are those high paying keywords if your content doesn't pique your visitors curiosity? Be passionate about your content, and the click through rates will skyrocket!