Do not let others influence your thoughts because you are the most trusted source of information.
If you really like the idea of investing, be sure to talk to your team, the community and the development team. If the community is large, at least the coin assurance you are investing is greater.
If the investment idea is good, but the support team is not good or too small, the high possibility of coin is not well developed.
I think that's a good way to ascertain the validity of a project coin but that not all you could do, there are other ways that could influence your thoughts which include knowing the team members who are handling the project,going through the project whitepaper etc