Reading structure
Higher highs + higher lows = uptrend; lower highs + lower lows = downtrend. A Break of Structure (BOS) continues the trend (price breaks the last swing in the trend direction). A Change of Character (CHoCH) warns of reversal (price breaks a swing against the trend).
Setup
Mark swing highs/lows on your higher timeframe. A confirmed CHoCH on a lower timeframe inside a higher-timeframe zone is a common SMC entry trigger.
Invalidation
If price makes a clean BOS the opposite way, your idea is wrong — exit. Good example: HTF uptrend, LTF CHoCH up from a demand zone → long. Bad example: forcing a long after a bearish BOS just because you "want" the trend to continue.
Common failure
Seeing structure that isn't there (over-marking). Keep it simple: obvious swings only.