Are your ads targeted to the content? The art site is getting a lot of religious ads... (and, maybe I glanced too quickly, but they don't seem to be on target?)

Also, the topics may not be ones that attract a lot of click happy visitors.

Sites that target products or product info tend to have a much higher CTR.

Evita

Seems like you're not sure how to define your sites so no one else is sure what it's about. I hear it's Art and Writing but I see a lot of religious references and adsense is picking that up too. The traffic is not targeted well thus the ctr will surely suffer.
Better define your site and the meta tags/title.

Your title on the one is "kokyunage." Is that a term that anyone might do a search for? I doubt it. The title should be ......ah, I can't tell what the site is about, that's your problem.

Improve your content, make it what the visitors would want to read. Also make the background of your website white!

If you focus on CTR then you have to see your visitor's profile whether they are habitual of clicking on Ads or just stick to the website they are visiting. Secondly providing diverse content is another way to increase your CTR because if a user finds nothing interesting or appealing in site he will Click on some ad or close the website. So both chances are there.

You can improve CTR by;

1. Doing a thorough keyword research and analysis
2. Creating compelling Ads/Creatives - Call To Action
3. Implement broad, phrase and exact keyword matches intuitively.
4. If it is Google AdWords work on improving your keyword quality score(s).
5. Most importantly narrow your target market to avoid wasting clicks and impressions