So far we have already covered how to improve the Adsense targeting (read here) and how to optimize the Adsense units (read here). The next step to increase your overall earnings is to find the best spots on your sites to place the ads.
The first thing to consider is to what extent the Adsense units will complement your content with relevant links without annoying your readers. Placing some ad units right on the top of your website will certainly generate many clicks, but over the long term it could hurt your traffic if readers stop visiting your site due to the advertising intrusiveness.
The smooth way
In order to decide what is the optimal Adsense positioning for your blog you need to define your priorities. If Adsense is not your main source of income or if you are concerned that intrusive ads might disturb your readers you probably should place the units separated from the main content.
A good place to insert Adsense units without affecting the user experience is at the end of single posts. You can use either the large rectangle (336×280) or the banner (468×60). Alternatively you can also try adding a Skyscraper to your sidebar or a Leaderboard to the footer.
People looking to maximize their Adsense earning will find that ad units close to the header or blended with the content usually perform better. On single post pages you can add a large rectangle right below the post title, either above the content or floating next to it.
On the Homepage you can add the Adsense units between posts and leverage link units. Link units look very similar to menus or navigation bars, therefore if you place those units on the right spot you could generate a very high click-through rate.
Every blog is unique
Understanding that your blog is unique is quite vital for placing ads successfully. You should always analyze what kind of responses you get from your visitors by placing the ads on different spots.
Finally, remember that readers are the most important asset for a blog (i.e. think twice before getting a couple of Adsense clicks in exchange for an upset reader).