Core concept
Treat backtesting as market context. Ask what changed, where it happened and whether price accepted the new information. A professional chart reader looks for relationships between location, reaction, volatility and risk.
How to read it on a chart
Mark the relevant area, wait for price to interact with it, then compare the reaction with the previous rhythm. If movement expands with clear acceptance, context is different from a weak touch that immediately returns to balance.
Common mistakes
The most common mistake is isolating one visual clue and forcing a trade. Another is ignoring volatility, session behavior and the higher-timeframe environment.
Practice drill
Open a clean chart and capture ten examples of backtesting. For each example, write the location, the reaction, the invalidation point and what would have kept you out.