[Note: If you already have a website, these comments are for you, especially if you started out with a hobby site. If you just want to build a get rich quick built for Adsense site, they may not be much help.]
I prefer to think of threads like this in terms of....
The Best Paying Keywords Available to You
So what are they?
For most of us, that depends on the topic of our websites.
OK fine, how do I find them?
First; Surf on over to the Adsense pages at Google.com and read anything you can find about Smart Pricing. You might just find a good clue there.
Second, after you've read the Smart Pricing stuff, grab a beverage of your choice and sit back and REALLY THINK about the topic of your website.
Think about every aspect of the subject that could possibly be relevant to your topic. I'm not talking just about the obvious stuff here. The obvious stuff is important, obviously.
But there may well be some aspects of your topic that are seldom discussed, or even thought about. Stuff on the fringes, stuff you might not see on every other site in your category.
Now go look at your site, are all those aspects you thought up there?
If they are not, or even if they are, go back and read the Smart Pricing stuff again.
Now sit down and write, or rewrite, some relevant pages.
As long as you are working on your pages, take another look at the heat map. Implement it as much as possible.
None of this is likely to net you $50,.00 clicks.
But there might well be, for example, some $1.00, 2.00 or even 3.00 ads available for quite a few sites with an $0.10 average EPC.
It doesn't take many of those clicks to really boost your income.
Did I mention reading up on Smart Pricing?