Good day, mates.
My strategy is to buy coins when the price drops sharply.
Sometimes I fail, because the price drops more than I expected.
But, to prevent this worse situation, I put 30% of my budget at the time of initial investment.
If the price getting down again, I put 30% more.
With this strategy, I am getting some money so far.
In conclusion, I recommend you guys to buy coins when they drops rapidly.
After sharp drop, there should be sharp rising.

In old times, I thought this is the best thing to do when price drops sharply. But when I watch some videos about trading, I learn about when we will enter to the market. We must buy our position when there is a big rally. It is easily to predict when there is a reversal using MACD or Fibonacci Lines. Well, I am not yet veteran using of that two indicators but I am pursuing to learn more.