I'd advice myself to not get involved into trading to begin with. Retail trading is just waste of time and money.
The second thing I'd advice myself would be to... Keep learning more about the crypto space. Maybe don't create a dozen of topics asking basic questions which could be answered with a google search, but yeah, with everything considered, there isn't one thing I regret about learning.
(Ok, maybe I convinced myself to buy a little more

)
Good idea, buddy. If you're new to trading or trying to teach someone how to invest their money, you should learn a lot and avoid getting involved in anything related to it until you've gained sufficient knowledge. Trading is not for the mentally weak, and you need to know what the risks are. You should also keep learning and ask questions about the things you don't understand. If you jump into trading without knowing anything about it, it's like starting a business without knowing anything about it.