There are many things to verify in order to know if an ICO is scammy. Normally ICO is used to raise money and let people hold the coin for a price below the speculative future price. However, many people are utilizing this to scam unsuspecting users.
The whitepaper. You should scrutinize the whitepaper well and try to get the use case of the Coin. This will give you an idea if it's feasible or not. The other one is checking the ten behind the coin. You should also verify if that is true and not just a jamboree. Others include having a functional website and responsive customer care center.
If the ICO is too good to be true. Please run from it. Follow your instincts too.