Short-term investment is like trading so I don't do that anymore, it's too stressful for me. I do choose long-term investment instead but it have to be a good project to maximize the profits in the long run. Out of ten that I picked way before the dump this year, I can still say I made profits from altcoins on the top 50.
I'd rather stick with what was recommended by the rankings that add more risk in finding gems that may end up just scams or rugpull projects.