Until quite recently you could distinguish between scam and non-scam ICOs looking through their whitepapers and website, but now swindlers have learned to create fake and believable whitepapers and websites. So now to stay safe - always look through the team, if you see that those people took part in other projects, which weren't scams - you can rely on them. And also remember the rule - never invest more money, than you can afford to lose.