how to choose a good ico is to see what the destination is in the shape of the ico and how much is it possible that ico can develop,
We can see the progress of ico from the whitepaper so we know when the ico rises and when the ico is lost from the market.
It will be so difficult to choose the best one and did you aware about most of the people are getting fallen into the fake ICOs? If we remember about the potential coin should be a coin with a lot of features and usefulness and it's also giving utility usage to the token. I know veil as the best one on privacy coin at the same level as monero, Ethereum with its utility usage and more good platform just like enjin and any other coin that can become strong candidates. These days ICOs depend on the market to gain its trend.