Most of the adsense publishers are running behind high paying keywords. But you should know about the truth behind high paying keyword. Basically High paying keyword doesnot work the way you are thinking about. 99% possibility is there that you have searched online for high paying keyword and started with one of them but this will bring you nothing but frustration in your early days of the page creation when the clicks earn you about $0.02 or $0.80 instead of about $25 or $75 as you have been expecting. This is nothing but the decision of Adsense smart pricing about how much you should get for the same click for which someone has got the highest earning. Remember that before paying you Adsense considers several condition about the age of your site, the quality of the content, the other contents of website and many more to count.
Remember, If earning would have been so easy from adsense high paying keyword and begins with just starting with few of these keyword, then I am sure that the fraud publishers would have grown millionare over night with that strategy. So, learn about adsense smart pricing and try to create quality in your site instead of running behind high paying keyword.