1. Never leave funds on any website or exchange.
Unless you are an active trader who has to have some portion of his holdings on an exchange in order to be ready to open or close a position at the right time.
2. Withdraw immediately to a wallet where you manage the Private Keys
It is always a good reminder for individual holders because "not your vault, not your gold," but not always suitable for businesses and companies, sometimes they are obliged to hire custodians for their coin. For example, MicroStrategy everyone is excited about has no coins in self-custody, which technically means they don't have any whatsoever.
3. Store savings on Paper Wallets generated OFFLINE
Most people, especially newcomers and newbies, have no idea how to generate paper wallets securely and properly, so I wouldn't recommend that on this board.
4. Memorize a Brain wallet phrase that only you will EVER know
The only case I can think of in which you can try to memorize your keys is when you are escaping the country hostile to cryptocurrency and human rights.
5. Keep 50/50 Crypto and Cash or other Liquid assets
6. Diversify your Crypto but keep mainly Bitcoin
By giving financial recommendations and advice, you increase the number of people who will blame you for their losses.
7. Do not trust anyone
I would put it differently, don't trust anyone blindly, instead verify and double-check everything you are told, look for answers and opinions in different sources.