I use to trade in altcoins on exchange. To be honest i lost in the last 2weeks,that my be because the price of btc has fallen to 3k around from 4.7k and also i got stuck in scam coins. If that happens to you dont panic just set your order to profit and forget that coin.
In reality every open position is right decision depending on time frame.Sooner or later price will bounce back to level which you opened that order.It can take years,months,weeks..That is why timing is important factor for traders..