The volatility of this market is very large. If you want to make money when you fall, then you need to know enough about this market and make profits from its fluctuations. I think this is very difficult, you can also At the lowest point, invest in some excellent cryptocurrencies to hold them patiently, and wait for the market to pick up and they will bring you a lot of profits.
I think you can make money after the falling of the market but you cannot gain money when market is still falling, the best thing to do is buy then wait for its price increasing. When the market is in the lowest point many people do nothing adnd some of them buy lots of coin because the price is cheaper but some those who have enough coins they hold it and patiently waiting for the market rising.