You stick to your trading plans no matter what happen. If you have a good foundation of your technical analysis and you have researched well enough on your trades, you will be more confident even if the price moves against your trades. It will take a lot of practice to control your emotions but you will be able to control it if you always try. And the fastest way to achieve that is if you are confident with your trades.
Its for sure that confidence is the key of hodling or having a patience. A sudden drop in price and your confidence of the upcoming months or years in the coin you bought will bring a good foundation towards a good handlinh or managing of your emotions. What am i doing in this crashes is just keep on learning and reading of any coins fundamental that can be a good choice to invest.