DON'T TRY TO CATCH FALLING KNIVES. You'll almost always get cut.
In other words, don't go all in on a falling security, commodity, or currency.
Wait for the item to find a bottom where it finds support and then starts to climb, then buy. You'll never be able to time it perfectly and you may miss the best low availabile (wait, scratch that) you always WILL miss the lowest low except by some miracle of timing. But if you keep averaging down until you've accumulated your desired investment, then that's your position and just hold on for dear life. For example: Let's say you want $20,000 of a security
You buy:
10 shares/coins at $1000ea ($10,000)
It falls. Oh no! What to do? Wait. Falls lower and you buy
10 more at $400ea ($4,000)
Now you have 20 shares/coins at $700 cost average ($14,000)
You're freaking out because you've lost money on paper and it's still falling. Now it's down to $300 and you still have $6,000 of your original amount left to buy in. So you buy 20 at $300 for $6,000
Now you own
10 @ $1,000
10 @ $400
20 @ $300
= 40 shares at total $20,000 ($500/share or coin)
20 at $500 is a LOT better position than 10 at $1,000 (if the value is there)
So the value is there, you've done your due diligence, then hopefully it's finds support and begins rising again (it could take a while). Still, getting back to $500/share break even will happen a lot sooner than getting back to the original price of $1,000/share. Now if the shares or coins were to return to your original purchase price, you've doubled your money due to cost averaging instead of just breaking even. 99% of people lose money. They lose it because they panic. Myself, I write it off in my mind as lost the moment I invest it, average down if needed, and the just forget about it.
If you're not able to do that, and that's mortgage or rent money, then you're in the wrong place and you should let someone else manage your money or wait until you can invest money you can afford to lose.