1. Position is the most important thing
2. Always set the profit/loss ratio above 1:1 (2:1, 3:1)
3. Always set stop loss below 10% of the account
4. Do not borrow, deposit too large (under 25X is safe)
5. Do not leave orders overnight
6. Adjust emotions when entering orders. If you lose, remove the other bets
Might also be good to add that don't trade if they're still new and check those trading exercises or simulators where they can trade without risking their own money. I think that's a good start for the newbies to have an idea of how it goes with trading so that they'll make themselves be prepared if it's about putting their money on the line as they trade. And as an addition to that tip, just don't leverage/margin trading, it's not really for the beginners.