On top of knowing where the previous days high and low is, it is important to watch for the globex high and low as well. These levels can act as key support and resistance point. One strategy is to go long at the globex low and short at the globex high.
Any break above the globex high is a long signal and any break below the globex low is a short signal.
One important pattern I have been seeing recently is whenever prices move below the
value area during the overnight session just to have it pushed back into value. This level below the value low pivot acts as key support during the trading day.