You must have a strategy and plan on what altcoin you want to buy, for me if the altcoin price is the same % as the bitcoin price there is no point to invest in altcoin, better to invest in bitcoin only. You must have searching and research what altcoins have a deviation increase from bitcoin, for example, if bitcoin price increases 10% then you must search for altcoins with have more potential increase than 10% i.e. 15%, 20%, or more. that's where the main point of profit is from altcoins.
I doubt altcoins are growing at least in price,I don't know about people buying/mining/getting them but the marketcap of such coins does not increase in the same way the leader does which is Bitcoin.Normally Bitcoin has increased in price well over 8000 dollars but I am not seeing such increase in the same percentage from popular altcoins like Doge,SHIBA,Ethereum,Ethereum Classic,Litecoin and many others,for me this is a clear sign that altcoins are not the people favorite's anymore like they were in the first bull run of 2017.