I always look out for
1. the team members
2.Advisors
3.The Concept, is it unique and will it work great
4.Do they have a prototype or a working project ( shouldnt be 100% done but can be tested and must reflect on their concept)
5.(optional) Is the company legit (Registered either by docs or EV SSL availability )
Similar. Also Realistic concept which solve real world problems. Based on this, I can understand they conducted a good research work, they know what they decide and for whom. In short, this is not a scum.