I think you can add up your assurance that you have invested in a right and good coin is through first looking at the white paper and at the team. If you can see that the purpose of the project is feasible and beneficial to many, you can atleast say that it is not a scam and if you take a look at the team and see good credentials towards it, you can say that it is indeed a good one. Always make sure you observe the project carefully and also monitor the price of their token if it is stable or more likely to go down so that you can avoid wasting your time for nothing.