With Arms Outstretched - S1-E9
Continuity mistake: When Lucas is showing Keith his tattoo, in each shot the sleeve of his shirt keeps changing from rolled up to rolled down.
What Is And What Should Never Be - S1-E20
Continuity mistake: Haley's lipstick gets noticeably thicker and thinner between different shots when she's talking to Nathan (when she drops over some groceries).
The Games That Play Us - S1-E22
Continuity mistake: Throughout the entire episode, Lucas' hair length ranges from being short to long.