Believe me
A social site named "PlentryOfFish" owned by "Markus" has earned more than $900k in two months while "ShoeMoney" blog earned more than $100k in one month. See the proofs here and here. So the good news is we should try now and reach there since it is possible.
Analysis of sites earning with Adsense
- Monthly visitors
Number of visitors is a huge factor considering the Adsense revenue as visitors help revenue increase; so having a healthy visitors base is a must. - Adsense ads placement
Many sites have been using text/image advertisements rather than going for text only ads or image only ads to change what user sees at first. Adsense text only ads are placed before/inside/after articles; but 250x250 / 300x250 ad formats are mainly used inside articles which would attract reads attention easily and quickly. Also one more point to note is the placement of 160x600 wide Skyscraper advertisements on to left or right bar running parallel to article content. Google Adsense Ad units are not much seen. One important point to note is the color matching of the ads with site content.
How can you reach there
Since every website or blog is unique, suitable adsense ad type, colors, sizes and places differ from each other; also whether to choose image only/text only or text and image also differ. Must choose between rounded corners(LINK) or not; depending on used web template. Best approach is to experiment many combinations of these and decide the best matching format. Adsense channels become handy in testing ads; as each ad placement can be assigned a unique channel which ease the experimenting and lead to accurate decisions. As an example; one channel may be named "leftBar.468x60.Pal3.21092007"; as the name suggests all features of used format, analysis would be really easy. Between one to two months will be enough to judge one advertisement format.While experimenting for best Adsense ad formats, one important point to note is " publishing valuable contents frequently is a must".