I think it was @jeffberwick who said (I could have heard that somewhere else though) in one of his awesome videos that his investment strategy is buy on dips. Never sell.

Looking back at my recent foray (last few months) into the crypto space, although there have been times I bought too high, I think my biggest mistakes have been selling coins in general. Sure, it's fun to sell a coin after it jumps 20%+ and make a few bucks, but I'm in this for the long haul, not daytrading. I need to keep reminding myself of this...sometimes my animal/money instict takes over!