do not hold too long, because it is risky. My advice is enough to hold because altcoins are very risky unless you hold USDT. so when the price goes up, immediately sell and when the price goes down you can hold
Never buy big green candles, always buy over several times. Learn technical analysis and risk management. It help you make and save money. Buy things that are bottomed out with good fundamentals, sometime it's more beneficiary to hold potential altcoins. Honestly, It's up to you on which altcoins you wanna invest.