There are basically 3 things to generate income through websites:
SEO, is search engine optimisation. Which means, the website is optimised as such to be visible on top by search engines. This process will make your customers know your website.
Website content: Website content is important to retain your customers. If your customers find your website useful they will come again.
ADs: This is the source of income. How your ADs are placed on the website will decide the number of clicks and give you money.