In order to overcome a loss in trading, one should continue. If you lossed an amount due to a mistake then learn from it, continue. You won't always win in such msrket wherein consistency is lacking. What wotks is deep analysis and luck most of the time. Predicting the best coins to trade is not possible. Selection of coins would depend on the trader's speculations of the market making it normal to sometimes lose.
Although you may not completely escape loss as an altcoin trader or crypto trader in general , but if you study the market well and get familiar with FA and TA you can trade with profits. One more thing you have to avoid greed, take your profit while you can.
Greediness will make you avoid the profit. If you wait further more for a greater profit because you are greedy, this will not allow you to take the profit while you can.
Avoiding the greediness and setting an accepted profit shall be enough as a trader.
Wanting for more is not a bad thing, there are times wherein waiting is suitable and times wherein it would be more risky to hold for a little longer. But I do get the point, trading do work more often on short term and investments do work more on longterm. But it still depends.
The only way to escape loss of your altcoin is by hodling. As long as you don't sell, the price is nothing but a number on the paper.
Holding won't be effective always. There is a chance for the loss to bloat if you will still hold and wait for things to recover because there are times that coins remain on the "dip".