Its hard to differentiate ICO scams and the legit ones. Well, I think that most of the ICO's out there were legit, you just need to do some research before investing to one. Read the whitepaper,  the road map, and join their community, you can also find a lot of ICO reviews out there on the internet. In order to prevent a loss of money, we must be smarter than those scammers, choose carefully to have a good fortune.