This video contains gobs of excellent advice. One of my principles is to get into 100% profit positions and lock that in so I'm playing with "house money." Another one is to never sell at a loss, but I realize I'm in the minority there. I'm a huge fan of DCA / Double Down, but because my risk capital is all profit that has previously been gained, I don't have issue with this philosophy.
The current market of crypto still affords a very decent terrain dominated by volatility, so these principles will work for me as long as that is true.
I can see how not selling at a loss might work, but I think it would require an extremely broad portfolio, of more than one asset class (i.e. a lot of non-crypto investments), and would likely require a large number of different investments, across a number of asset classes and sectors.