What is your current keywords? I bet most of them are easy to rank keyword but rarely to be searched and low paying ones. You can either target more well known for a good paying keywords like medical stuff. You will face a thought competitors by targeting more popular keywords but it is worth.
its depend on keywords different keywords gives different income and this all keywords on ad sense are changeable any time so stay updated your keywords
I see that you've low traffic and targetting cheaper keyword of "Pakistan". Not many good ad payers for that keyword
CPC really depends upon the competitions of the keyword you are targetting. You can use Google Adwords' Keyword tool to get an estimated CPC of your keywords.
hi all ads are not same in revenue.at first try to find which kinds of ads are give lots of sense then use the same type ads on your pages