The biggest mistake I see with people using Adsense as their monetization strategy, is they forget that Adsense is a CPC based network. You get paid per click, not by impression.
Yet over and over again I see people not laying out their ads on their sites to maximize their income potential.
Forget traffic for right now. I’m going to show you how you can close to double your income from your existing traffic with a few optimization tricks I’ve picked up over the years.
1. Use all your ad blocks, and make them big
Starting off simple.
Use all your ad blocks. In addition to increasing your chances for a click, this increases the ad spaces on your site advertisers can bid on and gives you a better overall RPM. You’re allowed to use 3 ad blocks and 3 link units for each page of your site. While I don’t normally use link units at all, I do use 3 ad blocks no matter how short my content is.
Forget all the other size options that Adsense gives you. Bigger is better. Forget trying to blend it into your content, just make them visible so people can’t miss it. I’ve done extensive testing colours and came to one conclusion: blending is not always the answer. As long as people can see them, they’ll click on it if it’s something they’re interested in.

2. Place at least 2 ads within the post content
I know, it’s ugly to have ads mixed into your content, but it’s where your ads can get the most exposure. I like to place at least 2 ad blocks within the content itself: 1 at the top and 1 at the bottom.
What works best for me is to put the first ad and the second one right after the content.
3. Use Red Instead of Blue
For the longest time, I had the same colour scheme to my site: black text and blue links. It worked.
But I noticed that using red links throughout my site instead of blue worked so much better. Maybe it has something to do with people’s natural blindness to blue link ads, but red far outperforms blue.

Try making all the links on your site red, and then use the same red colour for your Adsense ads. Don’t use a bright red, but more of a maroon colour so your site doesn’t look like it was built in 1999.

4. Use a Scrolling Ad Block
Google does list this as not-allowed in their policies. However, I’ve been using it for years and have even passed a manual review on my site. Use this at your own risk. It may be a case-by-case basis. If they see you are using it to manipulate clicks, you are putting your account as risk.
Ever visit a website and see the ad follow you down the page as you scrolled down? Implementing that into my websites dramatically improved my CTR and overall RPM.
http://oinsurance.net/increase-adsense-click-rate-faster/#4
Even if you do get permission to use it, it’s only against the policy if you hover it over your content. For example, if you had an ad block above your post title and it covered your content as you scrolled down, that would be against the rules.
If you have it in the sidebar, away from any content on the site, you’re allowed to use the feature.
For this, I like to use the Q2W3 plugin, which is free for WordPress users. Just activate the plugin, and you’ll see an option in your widgets to make them sticky.
Sidebar ads really suck for Adsense. But with this scrolling plugin, I improved my sidebar-ad CTR by over 150%.
The best ad unit for this? The giant 300 x 600 large skyscraper ads.

5. Use Text & Image Based Ad
With Adsense, you’re allowed to choose whether your ad unit is image based or text based. Unless you’re seriously in love with one type of ad, try using Text & Image based.

Using both text and image options allows more advertisers to bid on it (text ad bids and image ad bids) and increases your overall Cost Per Click.
Don’t expect to see an instant jump in CPC. From my experience, it’s not a huge increase, but over time, it does pay more per click than an only text or only image ad.

Great post, thanks for the info.