When buying altcoins make sure you buy them at its lowest value, it is still a good time to buy altcoins now because the prices are going down. Just make sure to hold them and don't sell them yet.
Yes before buying an altcoin do some research first if the coins you will invest is worth it. Buy at lowest price and hold it for sure you can earn profit in the future. Though price of alt right now is dump I believe it will rise again. Buy at better price were you can earn in the long run.