how to choose the most valuable altcoin

all the same
I think it's best to check on top listed coins like Ethereum, Litecoin, Xrp and a lot more. Checking on their history would enlighten you about their potential. As for me, trusting new altcoins has a huge risk so we better trust the ones that have passed all the tests of time.
yes agree with you, these coins like ethereum, litecoin, XRP, DASH top coins in coinmarketcaps and really be rise in the future. beside that these altcoins accepted by many exchanger so i think it make the altcoins using by many people in the world then has good volume in the market. and the last the price of these coins follow bitcoin price