I don't think that price growth could determine potentiality of coin. For me, I determine potential coin by uses. Its true few coins growth is good enough even there is no uses. But it's only temporary or by manipulated. But if you choose potential coin which have uses and team are too active to develop their platform then it might give you good returns on future.
So before invest on any existing coins you should determine which is potential coin and how it is. Don't just compare growth of price for alts.
What's your thoughts about it? Let's share knowledge and correct me if I am wrong.