Check the whitepaper first!   It's your money if you are going to invest at least pay a little due dilligence. Most of the scam ICOs just talk on 'air' and don't really make an effort on writing a good whitepaper. There are few more points and then you need to look at their combination as well. I'd suggest you to consider these points while making a judgement:

https://airdrops.me/crypto-guide/find-good-icos/