I know it's advisable to buy low and sell your coin at a higher price. What I don't understand is that when you sell high, do you suppose to buy so that your profit will not depreciate when the price is going low? I need an expert to clarify me, Thanks.
It all depends on the original goal of the purchase / sale. If, for example, I trade in order to transfer my profit to Bitcoin, then I buy and sell a coin:
1. buy at a lower price;
2. sell at a higher price;
3. leave the profit for hold;
4. for the initial amount of currency I buy a coin with which I will do the same as with the previous one.
This is one of the simplest options you can use.