When you decide to invest in something you have to do a lot of research before. Scams usually do not have public teams, do not have a good website or a well-written whitepapers. Scams looks shady and they do not keep in touch with their communities. They avoid questions and offer high bonuses for every investment.
It is quite hard usually to spot these kind of projects so be carefully and read every single article about them to see what others say about it. If something doesn't seem right, it probably isn't. Avoid greedy projects that raise tens of millions of dollars without justifying why do they need all those money.