Just as you stated about buying low and selling high, that is the only secret to being successful in crypto and most times, people get it twisted with the idea of holding bitcoin and treat it like something that is never meant to be sold.
I always tell people to buy at a certain price and when there is a profit they feel contented with, then they should feel free to sell if they want to and when the price rises to it's peak and begins falling, the need to use a stop losses shouldn't be overlooked.