It is not so much about placing dumb stop-loss orders or other trading techniques aimed at minimizing losses as about your mental disposition or general attitude to immediately get out of what can be loosely called a decision limbo when you basically don't know what to do. In other words, search for the exit where the entrance is and do that fast.
This is why a trading plan is important before making a trade. Many people do the mistake of just buying a coin because he read and heard somewhere that it's a good buy so he bought without even bothering research about the coin and what is the position in the market. He would only notice afterwards that it's a mistake he bought that coin when it dumps and he finds out it was pre-pump. This is usually applicable in altcoins.
Panic buying and panic selling makes the market movements rapid that's why many traders have bigger losses when this happen because they don't know when to exit and if ever there is still a chance to not be in a lose, they would still hold the coin hoping that it would go up more becoming more greedy only to see the price continuously go downwards.
Having a thought-out plan and good strategy is all important. As experienced traders often say, if you don't have a plan plan to lose. But then again it is not what I'm trying to focus on here. You can't foresee everything which is possible and still less which is impossible even though it still happens. But however good and broad your trading plan can be and no matter what you do or ready yourself to, you will get caught unprepared and off guard one day. This is the part I want to address in this thread specifically, and as I come to think the common tendency among most traders just to sit passively on their hands in such situations is the root cause of most if not all their woes and sorrows.