As I known, ICO is a kind of risky investment. Similar to the IPO which is the form of invite for capital investment, but when buying IPO, investors can research the information about the company they invested, find out about official finance reports and be protected by law when joining. In contrast, ICO projects are often rather ambiguous and unprotected by government so the risk is so high for investors.
So how to evaluate a potential ICO project, look forward to receiving comments from you

You better look for the team who are handling the project. As well as the whitepaper of the project. If you notice that it has a potential to be a good ICO then probably it better to give support with it. The whitepaper must contain all the important detail that the investors need to know inorder for them to decided wether they are going to invest or not.