So put your 250x250 ads on your left sidebar. And add skyscraper 120x600 or wide skycraper 160x600.
2. And every body always read your post, so lets put adsense below your title. Dont know how to put adsense below your title? Click here
3. Last tips from me is change your adsense type on your sidebar to an image and a text ads on your post.
Thanks, i hope it will increase your earnings, i've tried that on my blog. And that's work.