How to improve my blog with adsense service?

I think now I can't write a few articles than can improve my earning with google adsense because my English language is not good at all. I have just posted a few video about Khmer songs. I just try to find out the way to earn much money. And I just found a site that created by Cambodian blogger. The articles in that site told me some keys to success with adsense.
They said that the important thing to success with adsense is Keywords. We must choose some keywords that make CTR (Click Through Rate) pay earn much money. I have known some high earning keywords are including: American, Luxury car, Cell phone...etc. In those few keywords, we can earn from 10$ to 50$ per click. Now it's just a simple way to help me or other publisher to earning much more from adsense.