In order to place appropriate adsense ads on any website or blog, Google uses its advance internet search technology which based on website or blog content, user's geographic location and other factors. Mostly, websites or blogs that are rich in content, keywords, and updated regularly have been very successful with this advertising program, as highlighted in a series of case studies from the sites of adsense publishers. They are using text content on their websites to encourage visitors to click on their adsense advertisements.
If you are planning to start off making money with Google adsense, first of all you need to find your target market and niche market. After you have found the niche market, you need to search the related keywords and target for high value or high paying keywords. Then you can build your website or blog embedded with adsense ads and start writing content about your niche market. You should write unique, quality content, update regularly, if possible daily and maximize the use of keywords that are related to your targeted niche market. The search engines like web or blog pages which full of valuable and unique.
You can make your web or blog pages updated with unique and new content by plug in a few of RSS feeds that rotate in order to ensure that all pages are unique and very relevant to the topic. The presence of these RSS on your pages will be unique for the search engines and you will not be penalized for duplicate content. Since the content of your website is intended for the top pay keywords, therefore, the adsense ads on your website or blog is likely to be related to those keywords.