buy low and sell high is one of my best strategies. but I prefer to use technical analysis for it.i also use proper stop loss at my trade, because without stop loss a coin can dump a lot and i may lost all of my capital or stuck at one coin. also it is very important to do fundamental analysis before taking any trade. I also follow some top trader at tradingview and take knowledge from there chart. in this way I tried to stay risk free at my trade or i take very low risk at per trader.
That's also the point if you do not see always your buy and sell thats the reason you will loss some money. If the price of coins keep dump and you have a order of buying in a mid price of the token it is not worth it.
Though it is not that easy.
You might be able to see some indicators that it will go down or go up but you don't can't actually tell that it will be going in that lane. That is why as long as you've seen a price so low, better take that opportunity to invest or reinvest and hold for a longer period of time since that would be better than always looking at the price chart.