These candlestick reversal patterns use three bars for each signal. So, for example, a Bearish Engulfing Candles (which is a well known signal) will have a third candle which confirms the bullish move. This improves the reliability and reduces the number of signals.
Like any candlestick pattern these are best traded away from horizontal support/resistance and/or moving average levels. Overbought/sold RSI conditions are also good for confirmation as are classic pivot points.