Try to find out the team working for the ICO, you can find out if them mostly are anonymous random person who don't have any profile or reputation than better to stay away from that ICO. Learn to distinguish them. There are many guides, tips and sharing experiences on the Internet. So go ahead. From myself, I will add only what is hard to find, and this: view the cryptocurrency code on github, check the team for realism, as well as experience with large projects and try to calculate the amount needed for this project. If their amount is more or less (much) then you should refuse.