As the question reads. For me:
- The concept/vision - is it innovative? does it solve a real world problem? is the problem it solves something I am interested in?
- The team - Size and experience.
- How the coin relates to the concept. Is the coin a key part of the platform? Are other payment methods available to users, etc.
I think this lists are good. Usually, new concepts and ideas attract investors. If I were to invest big amount of money into an ICO, I would look for an ICO that is something new and that people would really use in the future. And, the project should be user friendly and not complicated to use. People nowadays are lazy to understand the whole concept of things. So, everything should be made simple.