You just need experience to learn it. It is not easy to just say because there is many things to consider. Every coin has unique parameters and design. Everyone seems to have their own opinion on what is good, that's why there is so many coins out there. A coin for every option basically. One single coin for everyone to accept is just not possible IMO. Keep in mind how long a coin has existed too. Some are launched very recently and there isn't a good history on them, and haven't played out proving a test of time so be careful. Hundreds of coins have come and gone.