I have a blog.It has got PR 4 in the latest pr update.I have placed some google adsense on it.But up to now,I have got few earnings from the blog.I don't know why.Who can help me? My blog is http://www.171english.com Your advice will be much appreciated.
I'm of the opinion that you have wrongly placed 120x600 ad. Moreover you need to blend it with your content.
What is your daily traffic. If got good daily traffic, then, you mean rethink your theme and ads. placement.
Not so good ad placement, not a lot of traffic and geek oriented blog = 100% failure. Oh and I forgot also the duplicate content since you don't produce content but copy it from somewhere else, so it's now 110% failure.