Continuity mistake: When we first see Aang in the stocks, Sokka advises him to use his Airbending to escape and begins "imitating" Aang's kata. During one pose, we see Sokka is wearing the boomerang, or at least the sheath it was in, that he had to leave behind at the beginning of the episode. He wasn't wearing it before, isn't wearing it after, and doesn't actually get it back until the climax.
Continuity mistake: When Katara is trying to heal the wounded earthbender, she gives Sokka the idea to take down the drill from the inside. Sokka then stops her from saying anything while she is sitting down, she is wearing her necklace. But when she stands up in that same shot, the necklace is gone, like they forgot to animate it.