For general website performance and stickyness I've added several things to the original website:

1) bread crumb links on every page
2) in-parapraph links
3) a 'related articles' list at the end of many pages
4) occasionally an authority site external link (opening in new window)
5) search function on many pages

I would assume anything that keeps visitors on site will improve unique visitor CTR. However, these additions may actually lower CTR since each visitor is going to many more pages (hopefully).

I still have many more in paragraph links to add.

It is my belief that better performing web pages can increase the likelihood of ads being clicked. As sailorjwd pointed out, keeping visitors on site longer should improve CTR.

Here are tips I use for better page performance:

1) fresh content weekly (depending on your niche)
2) bread crumb links on every page
3) page size less than 16K (for optimal load times)
4) allow social sharing and publishing from each page
5) light graphics (optimized JPG, GIF, PNG images; no Flash or Java)

Great question. I don't want to hijack the thread, but got thinking about social sharing, etc. Any ideas about how to allow this from static html pages?

I don't want to convert the pages to blog like pages, but wondering if there's a simple way to add something to each page to allow comments, sharing, etc?

We built our own javascript include that displays our "share this" options.

Comments could also be added using Ajax, but they would not be visible to search engines (right now at least).

If you need comments to be visible to search engines, you might want to consider making the page dynamic.

Hope this helps.

As for the original question, I think that beyond keeping folks on your site, another way to improve earnings is to make your site more valuable in regards to what buyers might be looking for before they buy. Ads are often geared towards getting someone to subscribe or buy something. If your site is the last stop and helps convince them to buy, then your ads will be converting sales for advertisers, and in turn make your ad slots much more valuable.

Regarding improving CTR, sailor's comments hint that the improvements may cause CTR to lower statistically because of increased impressions, while improving overall earnings.

However, these additions may actually lower CTR since each visitor is going to many more pages ...

There are many social media gadgets that can be added to a page. You can see them in action on many of your favorite sites. A gadget that includes a tell-a-friend function in addition to the facebook etc. stuff should do the job. I've added one of these gadgets and experienced an increase in traffic from sites like Facebook, with people sharing my pages from Facebook itself, in addition to the tell a friend sharing.

[edited by: martinibuster at 9:09 am (utc) on Oct. 26, 2009]

I think limiting (even removing) all outbound links that are not Adsense ads is key. I have tested this numerous times over the years since Adsense came out, and each time this one simple thing shot CTR up. Every time. It isn't feasible with a lot of sites, I realize, but if you have it within your power - and if it doesn't hurt your other income sources - just eliminate or reduce outgoing links. Essentially, you're taking away one of the options for visitors to leave your site without putting some coin in your account.

taking away one of the options for visitors to leave your site without putting some coin in your account

That's a certain way to sabotage the quality of traffic that you're sending to your advertisers.

Hello, smart pricing!

swebbie is onto something. This is something that I have done, where I had pages of content about a topic that were linking out to some sites I didn't care about or need to link to. The content pages in this section stood alone as authoritative pages about the topic, they didn't need to link out to another site for usefulness or validation of their information. From a link graph perspective, I didn't think the links were helping me. So I removed the links and had a permanent earnings spike.

This is why I think it didn't cause smart pricing: It's not forcing people to click. It's removing a link that competes with the AdSense links. Removing the non-productive non-earning link removes a non-paying competitor of the AdSense ads. My pages are authoritative, the outbound links served no function. From my actual experience, what swebbie describes has worked. No smart pricing. I am not saying this works in all situations, and also would like to remind that removing links may negatively affect your rankings.

[edited by: martinibuster at 8:21 am (utc) on Oct. 26, 2009]

Page speed is extremely important in my opinion. While running a couple e-commerce sites we have seen conversion improvements after making the sites faster.
I believe the same rule works with content sites. The faster the site loads the more eager I am to click on another article.

If you place your ads on top, making your page load SLOWER might actually increase CTR. For the wrong reasons, that is, but still ;)

Also, place your outbound links preferably at the bottom of the page, in a 'resources'-like section. That should shave off at least some premature exits.