If they have legal documents on their business, trust to their potential that they can make their business successful and at the same time trust to them that you will get an income in the end.
Investing on Cryptocurrency is very risky due to it's volatility but it is more even risky if investing on ICOs because they're seems more valuable when you're looking at their project or ICO profiles but in the real world like when it hits Crypto Exchange and being listed on coinmarketcap.com then that would be the real score of the new Altcoin.
That's why I intend to invest to new altcoins that being listed on coinmarketcap.com because they're already passed the ICO stage and they're even reached their soft and hard caps along their way.