Which type of ad should I choose and where should I place them?
Every website and blog is different and each website owner should experiment with what works best for them
The most profitable type of ad are “Ad Units” or “Adsense for Content”. Other advertising options are also available. They are, Adsense for Search, Link Units, Mobile Content (for smart phones) Ads for Domains (domain parking), and Ads for Feeds.
The ads that are displayed highest on your web page will pay the most due to the fact that individual advertisers pay for positioning.
See the Hot Spot map below for suggestions as to the best location for an adsense unit. The brighter the orange the better the placement.
As you can see from the image, the best placement is just above your primary content.
Remember, the ads that appear highest on your page will pay you the most money. So, if you position only one ad in the hottest area (just above your main content) you visitors will be more likely to click them and you will earn the most money from them. But by the same token, if you use all three top and top left positions, the area just above your content (the hottest spot) will now be the third ad and will pay less. You are only allowed to place three ads for content on each page.