Histograms such as MACD histogram or my Ichimoku histogram give two kind of trading signals. One is common and is triggered on each price bar. The other happens less often but is extremely powerful.
The common signal is triggered by the slope of the histogram. When the most recent bar is greater than the one before, the slope is bullish. This is saying that bulls have the situation in control and that it is time to buy. When the more recent bar is lower than the one before, the slope is bearish. This shows that bears have control and that it is time to sell. When price action is going in a direction but the histogram in another, it tells us that the trend is losing its strength.
Buy or go long when the histogram stops falling and rise a little. Use a protection stop under last support.
Sell or go short when the histogram stops rising and falls a little. Use a protection stop above last minor resistance.
In lower timeframes, it is not be worth to buy and sell every time the histogram reverses. A change of direction of the histogram incline is much more significant on higher timeframes such as Daily or Weekly.
Bearish divergence: Sell or go short when the histogram is reversing from its second lower high and price is on a new high. Place a protection stop above the new high.
Bullish divergence: Buy or go long when the histogram is starting to reverse from its second higher low and price is on a new bottom. Place a protection stop under the new low.