Define invalidation
An invalidation point is the price behavior or market condition that tells you the original idea is no longer working. It should come from the chart and thesis, not from hope.
Match size to risk
Position size should reflect how far away the invalidation point is and how much loss you are prepared to accept. Conviction alone is not a sizing method.
Expect uncertainty
A well-planned trade can still lose. The goal is not to avoid every loss. The goal is to keep one outcome from becoming a decision you cannot recover from.
Beginner takeaway
Risk comes before reward. If you cannot explain what changes your mind, the trade plan is incomplete.