Google Adsense
 

The simple answer is with a website. But it is not as simple as that. The real money makers are people who pick a subject and focus deeply on it. They fill their websites with a huge amount of superb content. They also use keywords to draw people to their website through natural searches. The successful sites will attract the correct and relevant AdSense ads to their website. If you produce a website that has no theme or common focus then the Google AdSense program will not place good and related adverts on your website. The whole idea is to build a website that is logically themed around one main thing.