So, before the market opens at 9:30a.m. EST (8:30 CST my time) I frame the highs and lows of the pre-market in the SPY. These levels are indicated by purple horizontal lines in the charts that follow (where p/m_H refers to pre-market Highs and p/m_L refers to pre-market Lows). The vertical blue dash line indicates the open of RTH. In the chart below we can see how closely this compares with the futures globex market on the right (the E-mini S&P in this example):
Along with the p/m_H & p/m_L I like to extend Fibonacci projections off these levels in 50% increments. So, starting with trade from Monday May 21 here we have the SPY with pre-market included.
Monday was a trend day up, but notice how price behaved at both the p/m_L & p/m_H before breaking out:
Tuesday May 22nd; a test higher (just beyond a 50% projection of the overnight range) and a test lower (nearly to the penny of a 50% projection) before settling back around the previous day's close
Wednesday May 23rd; A narrower overnight range where on the open the p/_H was rejected and price moved swiftly lower to a 100% projection of the overnight range. Eventually however, price rallied higher, extending to the 100% projection on the upside (notice how it gets caught up on the p/m_L, needing to pull back before it can take off).
Thursday May 24: A very wide o/n range and being a range-bound market in this instance, price tests both extremes:
Friday May 25; A quiet pre-holiday environment where price based along the p/m_L for most of the afternoon before breaking lower and reversing on the 50% projection.
Anyway, to get an idea of where you're going it helps to know where you've been.