Sure, it really isn't anything special. I essentially treat the site like a magazine and sell advertisements on a monthly basis because that is the easiest thing for both myself and advertisers understand.

The site runs on WordPress so I just use one of the ad rotation plugins available [adrotate pro]. Most campaigns are for some set number of weeks or months and the plugin takes care of that.

I track clicks and advertisers track referrals traffic plus whatever other metrics they want to on their own websites. Because a number of advertisers renew regularly, I trust that they are happy with the results they are seeing. For payments, it kind of depends on the customer, but basically I just invoice them.