The ratio between high, low and time compared with the typical (long term average) volatility of the market. Examples for a single stock: high 135, low 100, time between high and low: 12 month -> average trend; high 150 -> overbought; high 120 -> correction.
Place two LCDs, One for watching chart and another for watching porn. Let your sixth sense tell you this, if your are losing your erection, it might be high probability that trend is coming to an end