Everything a candle can tell you comes from the relationship between those four numbers — not from the colour alone.

• Body: the distance between open and close. A long body means one side dominated the whole period.
• Upper wick: how far buyers pushed before being rejected.
• Lower wick: how far sellers pushed before being absorbed.
• Colour: green or white when the close is above the open, red or black when it is below.

A long lower wick means price was pushed down during the period and bought back up before the close: sellers tried and failed. A long upper wick is the same story inverted. A candle with almost no wick means one side controlled the period from open to close without meaningful challenge.

• Doji: open and close nearly equal — indecision, and often a pause before a decision.
• Hammer: small body, long lower wick, appearing after a decline — rejection of lower prices.
• Shooting star: small body, long upper wick, after an advance — rejection of higher prices.
• Engulfing: a body that fully covers the previous candle's body — a decisive shift in control.

A hammer in the middle of a range is noise. The same hammer at a level that has held three times before, on above-average volume, is information. Candlestick patterns are modifiers on an existing thesis, not a thesis by themselves.

Timeframe matters just as much: a bearish engulfing on a 5-minute chart inside a strong daily uptrend usually resolves upward.