Many things you should consider to choose an ICO. Since many scam ICOs, you are better to be more careful and selective. For me, these are the common things that should be analyzed before joining an ICO.:
1. Team Members Information: Google on linkedin, social media, wikipedia, and other sources related to the team members.
2. Project Ideas or Concept
3. The product or MVP
4. Whitepaper
5. Roadmap
6. The competitors
Do own research and observation for those factors above. At least, ensure if everything is good enough and nothing suspicious.