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.
Three things look for in an ICO, I feel important are;
1. Whitepaper
2. Vision
3. Platform [on what the tokens for the ICO are being build upon]