When you are parking your domains you want to get paid the most you can per click. To do this you must know what keywords pay the most while keeping your content relevant to your domain. There can be a huge difference in what advertisers are paying for search terms.
To find what keywords pay the best I like to use Google Adwords. Even if you don't have an account you can use their tool. You can find by searching Goolge for “keyword tool". You should see the Adwords keyword tool as the first result.
Once you are at the Adwords keyword tool, put in your keyword and enter.
Then you add a column to show CPC. Put in $100.
Once you get your results you can then sort by price. The highest paying related keyword will be at the top. That's all there is to it. Pretty easy! Don't expect to get to get amount shown, there are a lot of other factors that come in to play when your click amount is calculated.
One thought before you pick the top keyword each time. Because they are expensive, the highest paying key words may not have as many advertisers bidding on them. Therefore, there may not always be these high paying ads on your parked page.
Another thing to look at is advertiser competition and search volume. You need to strike a balance with all of these factors while keeping your keyword relevant. In reality choosing a high paying keyword is really a balance of PPC, search volume and advertisers. Find the right balance and you'll be getting the most revenue possible from your parked domains.
Experiment, and try to look at your overall performance not the number of clicks. The most clicks may not be making you the most money.
Visit my Domain Parking Blog at http://www.popularparking.com Domain parking, affiliate information and discount codes. How to make the most money from your domains.