Understand your true exposure when trading with leverage.
Leverage amplifies both gains and losses proportionally. At 10:1 leverage, a 1% move in the underlying = 10% gain or loss on your equity. At 100:1 (common in retail forex), a 1% adverse move wipes out 100% of your account.
Most professional traders use 2:1 to 5:1 leverage at most. Prop firm trading often involves high notional leverage but controlled by strict stop losses and position sizing rules.