This 15-min chart of Crude is zigzagging in the overnight session until it reverses and leap vertically in the regular session. Notice that resistance level (the line below), it is a powerful point where the market bounced opening for an entry above that trend line (above). If you understand the trend(s) as what Trader Vic of the Wall Street Master implies, you can have an idea how to make/put trades, and this is one of his example, the change in trend.
For the Gold 30-min chart second below, it made a tight consolidation in the overnight session for its powerful reversal. Price action and level observation (the support/resistance) is the right approach to deal in this kind of trade.