The most important is don't waste your time on asking questions.. just see the threads about it how to get more money..on adsense.. you'll get thousands of tricks.. and work on your content..not the money when you have good unique contents advertisers will sure bid high for your site..
If you have to increase the earnings, then you need to blend adsense code according to your site contents. I mean for the visitors ads should look as if it is your website contents. So, try to change the ad colors that matches your site text colour and background. This will definetly help you out. I am earning really good money with adsense.!
Did this happened only once or is the average for e.x 100 clicks? Anyway it might depend on the niche and the ad. Some websites earn less than $0.01 and some other more than $20++ for a single click. This happens all the time. and it all depends on several factors. If you have a website about y niche and you know that the average earn per click is e.x $0.50 then it means that G! estimates that your website is not very good for that niche so it gives you all the lowest advertisement. Just add more real content, put less ads and promote it more.
What you earn from asdsense depends on few things like the Niche, which I think is very important. Then comes the sources of traffic. And the origin of traffic. Traffic from USA/UK pay the best. Anyway, you can make good money with any Niche if you can get lot of traffic.
Insufficient information to make an informed guess. There are too many reasons such that to say it is any one thing would be pure, unsupported speculation...do you have any specifics that you can give us?
Just try to use this map as ads placement in your site:- prefer to put your ads in the dark er places more than in the lighter places... Note:This is from adsense guiding points. Article Source:- Make Money In Pakistan