1. Not knowing the difference between trading Spot and trading Futures
The Mistake: Many newbies forget that in Futures you’re not buying the asset, but signing a contract with borrowed money from the exchange. Your capital acts only as collateral (margin); if the price hits your liquidation point, the system automatically closes your position and you lose 100% of your money on that trade. THE FATAL ERROR is not doing your risk management, meaning not setting a Stop Loss.
My Advice: If you're going Spot, diversify. If you're going Futures, risk management is key: never risk more than 1% to 2% of your total capital per trade. Always use a Stop Loss so the market doesn't decide your exit for you.