How to avoid scam sites when earning money from online?

1. Research the site before joining/investing.
2. Check the site age, search it in search engine(google) before joining/investing.
3. Visit their forum to know more about them.
4. Some fast paying site is worth to try even it's new,but slow paying sites (including site that very slow to reach payout) not worth if it's new,as they might close before you reach the minimum payout.
5. Don't invest in any sites if you are new to the online earning.