How to easily get accepted by an advertising network?

Getting accepted by an advertising network could be tricky. However, once you get accepted by an advertising network, you can easily start generating revenue. You could get accepted by ad network in many different ways. For example, you could design a professional website. There should be no "Uber maintainence" pages. The content on hr website must be fine. You should avoid subdomains. So what are some other was to get accepted by ad networks?