These days they are very strict about content these days. You can’t use copyrighted, Duplicate or Warez content. You can’t even link to a site with warze content. Also don’t use PTC, GPT type referral banners or links along with AdSense ads. Same about contentless sites, You might get away for a while but sooner or later you will get your ads disabled for the site unless you area premium publisher.
Low quality traffic one of the most common reasons people get banned these days. Should stick with mainly Search engine and social media sites. If your site niche is New York Car rental then having China traffic to your site can get you banned. So you have to monitor all your traffic sources.
So here’s some tips and facts about Google Adsense. I hope it will help you in your journey in making money with Google