This is going to be your best friend as long as you are doing Adsense to make money. This tool helps you identify which keywords are getting the most money on the Adwords platform. There are certain industries that pay very well per click like Real Estate, Law, Insurance, etc. These are just a few categories that can make you some money per click. 

Using Adwords Keyword Tool can help you find these advertisers and see what the average bid is. The higher the bid is, the more money you can make for that particular keyword. Therefore, you can create a blog or an article around these high bid keywords.

Your content has to be consistent with the keywords you are trying to monetize for your ads. In other words, if you are trying to make money from the keyword "tax attorneys in Florida," then you will need to make sure you stick to the subject and not deviate. If you change any subjects or keywords, then you can potentially get less paying keywords. 

The more you write, the more you will be able to monetize your site. Sometimes it can be a curse for you to write articles that are too short because the ads might need more content to monetize the ads. That is why some people grow a little frustrated when they notice that their ads aren't monetizing because the content might be a little too short. I would recommend that you write a minimum of 350 words so you can be sure to monetize your content.