buy low sell high, as simple as that. you earn more profit if you have more BTC, but you can also lose a lot of money if get unlucky.
Best advice I have seen for a long time
Seriouly, if it was that simple why don't everybody do it? Also keep in mind, in order to make a profit on trading crypto, then MUST someone have a loss. Its pretty easy to guess where the loss come from, I think the biggest source is newbies getting in trying to trade, they are being ripped of. If you try to sell/buy you will in some kinda random altcoin which is moving, it is pretty clear that it the same person or entity making buy/sell orders. It is super coordinated and designed to rip "new traders" off.