A advertising web site

Advertisers are only willing to pay for space on your site if they know you can get their ads in front of HUGE numbers of qualified leads.
In order for this revenue model to work for you, you need to have a lot of highly targeted traffic coming to your site.
Remember, on the Web, all conversions related to advertising are trackable, which means advertisers will know exactly how many people click on the ads on your site, and how many of those people actually convert into customers. They're not going to pay you unless you send them enough paying customers to cover their advertising costs.
So... what does this mean for you?
It means you have to be able get your site listed at the top of the search engine results, in order to guarantee high traffic numbers. And that means devoting many hours a month to optimizing your site and using strategies such as article sharing, blog writing, and forum participation to build a huge web of links all pointing back to your site.
Again, I have to say -- that's a whole lot of work simply to advertise other people's products!
Of course, you can also put Google Adsense ads on your site -- but since you're only going to make pennies a click for those ads, unless you're getting thousands of highly targeted visitors to your site a day, all you can expect from Google Adsense is a little extra pocket money each month.