Yes obcourse buy low and sell high is the golden rule in trading and in the way you can earn a good profit but not only that you can also learn more about crypto. When you doing trading you need to learn to control your emotions too to avoid loses.
For sure everyone here is using trading to earn money and the best way to earn money it trade when the price is low and market is red then; later on sell it for very high price, I think the best trading is long term trading, as day trading is good buy it needs a lot of time first you spend to search about it and know all the strength and weakness of trading, so I use to keep my profit saved and then trade for long time finally I end up earning high amount of profit.