In order to trading, we must look at how much a coin decreases and increases and within what range this coin is moving in the market. We have to buy that coin after coming within a minimum range. And when everyone starts buying this coin, the coin will suddenly go up and you have to sell it at that time. This way you can easily get 10 to 20 percent profit.
What you are describing is what it's called a ranging strategy, you see the market moving in a kind of cyclical manner and you take advantage of that, that is not a bad way to trade assuming that you know how to trade under those circumstances, there is just one small problem, you cannot trade like that all the time because markets have a tendency to trend up and down, if you happen to sell your coins thinking that the market has reached its maximum potential you could easily be surprised when it keeps going up and you will lose a lot of money that you could have won have you kept holding your coins.