How do I protect profits on a winning trade?

Trailing stop loss: as price moves in your favour, move your SL up (for longs) to lock in profit. Common method: trail SL below each new swing low as price makes higher highs.

Partial profit taking: close 50% position at 1:1 R:R, move SL to breakeven on remainder. This ensures you never turn a winner into a loser while still participating in extended moves.