We're getting good click-through rates by using very simple web pages built using basic Site Build It templates, with the ads high on the page.
Placing the ads at the top left or the top right, and using a box or a skyscraper ad seems to make little difference in my experience. You'll have to test to see what works for you.
One of the most important points seems to be to have a simple page in which the ads are prominent.
(Others insist they get better results by making the ads blend in, as though they're part of the site. Go figure! Perhaps that works for suspicious marketing audiences and prominent ads work better for less sophisticated audiences? Just a theory - definitely NOT fact.)
Perhaps most important of all, the ads need to be displaying items your visitors are interested in. You may be able to improve the ads that are being displayed by tweaking words on your pages - using all the normal SEO techniques.
A site which gets lots of repeat visitors has a much lower click-through rate than sites which get lots of new visitors.
To increase the effective CPM, you'll need to be in an industry that has high-value keywords.
I wrote a long article on how to boost your AdSense revenue:
I deleted a section of your post. When you joined AdSense you agreed to AdSense's Terms of Service. You agreed not to discuss details of click-through rates etc. It's annoying, but that's the way it is. On this forum, I have to obey that rule because I don't want to get kicked out of AdSense.