For me I think its the project is widely accepted by the community, I'm following the feedback of the people about the certain ICO i'm looking to invest. If I see a good response from people then it would likely to succeed, also I'm looking the use-case of the project if it the product would click to investors, right now I'm looking to invest on VTOS, OPP, and menlo.one.
I have to say, all three are good choices, but I think Menlo One is on an entirely different level because of its unique project and I can 100% say that the team working on it is 101% legit.