I'm not really good at trading but I still know some ways to find it out
)
1. You can know which altcoin will have good potential to pump in next few day by collecting the news about it on twitter or you can easily find out the
news on Coinmarketcap
2. You can join some trading signal group like Cryptopredict.me, The WOLF OF SiGNALS or use Gunbot software to know.
3. I don't really know if this one is right or not, you also can know the potential by looking at the trading volume of any cryptocurrency, when It's listed on
any exchange for only 1 day but the trading volume is nearly 1m$ or maybe more, I think these coins have very good potential in the future.
This all I know about this case, I'm not a good trader but still hope this help