A Trend Must Exist - A trend must exist before a reversal of thetrend. There can be no reversal if a trend does not exist in the firstplace. A reversal pattern that follows a large trend will have muchmore movement to retrace, and so the strength of the move after thereversal pattern will likely be stronger.
Trend Lines - The first precise signal that the trend is ending isoften the failure of a trend line, that might also come along withoscillators that show overbought or oversold before a reversal patternoccurs. Note that the intraday break of the trend line is notsignificant until a daily candle closes through the line. The chartbelow shows a trend line that is broken on an intraday basis before theprice recovers. The first strong signal that a reversal may be comingappears when the price closes below the green support line. The pricesubsequently rallies to form a double top, but it does not hold thesegains.
Time Frame - Like relative highs/lows and trend lines, reversalpatterns gain greater significance if they occur over a longer timeframe. A head and shoulders pattern that takes months to develop willof course signal a reversal of a much larger trend than a head andshoulders that takes place intraday.