Tried and tested tips:
1. Invest bitcoin if the company is 0-10 running days.
2. Make sure that the deposits, withdraws and member is increasing.
3. Search for more information about that company.
number 1 is my friends tips too, he said this is just avoid if the site is getting scam and the percentage for paying the member is big. number 2 i think all the site investment will increasing day by day. number 3 this is the important thing when we want to make investment on the site because we should know all about the company so we can save when we want to make invest.