This includes engulfings, morning/eveningstars, haramis, etc.
Upper Shadow/Wick: Difference between the High and Candle Open if it's a bearish candle, High and Candle Close if bullish candle
All these formations give signs, but by no means do they have a 100% strikerate. Like always when trading, manage your risk, and only enter a trade when your system tells you to do so.
Hope this somehow helps the less experienced people here on Twitter.