What the levels mean
After a strong move, price rarely goes straight on — it retraces part of the way before (sometimes) continuing. Fibonacci levels estimate how deep that retrace might run: a shallow pullback stalls near 38.2%, a deeper one near 61.8%. The 50% level isn't a true Fibonacci ratio but is widely watched.
These are zones of interest, not magic lines. They matter because enough participants watch them to make them partly self-fulfilling — which is exactly why you confirm them with other context.
How to draw it
Anchor the tool from the start of a swing to its end — low-to-high in an uptrend, high-to-low in a downtrend. The retracement levels then plot between the two. Use clean, obvious swings; forcing fibs onto messy structure produces noise.
The 61.8% level is the common 'last line of defence' for a trend — a retrace that holds above it keeps the higher-timeframe structure intact, while a decisive break through it warns the move may be failing.
Using it without over-trusting it
Fibonacci is strongest when a level lines up with something real — prior support/resistance, a moving average, or a volume shelf. A confluence of a fib level with horizontal structure is far more useful than a fib level alone.
Treat it as context for where a pullback might pause, then let price action confirm. Define your stop beyond the level and size the position with a plan — never enter just because price tagged a fib.