Why did my eCPM rate decreased in google adsense?

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I have placed adsense on my blogs.One of my blog is http://www.all4beauty.blogspot.com .In order to increase the page counts i have participated in link exchange program but then i have noticed that my eCPM and my earnings have stopped showing any change.Then i removed my links from those link exchange programs but now i have noticed that my blogs earnings have decreased and the earning per click has become negligible.Please tell me how to increase my blogs earning per click.I havent participated ever in fake click exchange programs.