For me, Volume is the most important indicator and I can easily identify a worth it altcoins to buy through looking and analyzing the volume. Most of the shitcoins doesn't have good value and good volume. Those shitcoins should be avoided in order to not experience huge losses and red portfolio. A good altcoin for me have a daily volume more than $10,000,000. If a certain altcoin has that volume consistently then it is one of the good coins, I also suggest that the altcoins should be belong at the top 100 in coinmarketcap.com.