I'm mainly looking at 4 things, plus a little bit of gut-feeling:
1. How is the team? Who are they? What are their goals?
2. Is there something behind their token sale i.e a solid implementation?
3. Market feedback, how do people react to it?
4. Token sale parameters: how many tokens and why the amount? How many tokens are sold? How much for the team? etc.
I found a quite interesting project some time ago. It's called GetGame.io (
https://getgame.io), it's a blockchain based game development platform. I run it through my checklist and I think it's quite a promising project. It has a solid team and a solid purpose (to make game development easier and more accessible), they have a strong implementation (a platform for game devs with all the necessary tools), feedback is very positive and they are only issuing 500k tokens for the ITO, indicating that they value their backers and don't do it only for the quick money grab. I suggest you check it out yourself, their ITO starts on the 30th of November 2017. I personally have high hopes for this project.