The crash will teach alot of people a bitter lesson and they will learn from it,
One piece of advice that is generic but not necessarily, other than really separated by trends and the underlying community for the business rule is profit-regeneration-profit. In fact, never forget to take it seriously until you really realize how the market turns. There are crashes and there are explosions, who doesn't expect that?
I don't think people like to learn lessons though:) Especially not when they never came in with the intention to learn. Expectations are a weird thing for a lot of normal people. Even myself, knowing what to expect, I still feel disappointed or elated when things go the way they should even when I'm no longer trading or investing in ICOs! Still looking at tokens I never got or I used to have. Such is the life if we live by markets:)