Continuity mistake: When Hook comes to see Emma at the sheriff's station, his earring disappears when she kisses him goodbye.
Continuity mistake: Emma has a flower tattoo on her left wrist. Throughout the series, there are subtle changes in its design, and its position on her arm. For example, when Emma is sitting at the table with Mary Margaret in "The Thing You Love Most", the tattoo has six petals, and is located about an inch below her hand. When she's on the phone with Ruby in "Red-Handed", the tattoo is much bigger, and the petals are arranged differently; it has also moved further up her arm, and is almost touching her hand. When she's arrested in "Tallahassee", there are five petals instead of six, the petals have a rounder shape (in "Red-Handed", they were rather pointy), and the tip of one of the petals is touching her hand. When she pulls her hair behind her ears at the tavern in "Snow Drifts", said petal is thinner, and is no longer touching her hand. When she touches Hook's face in the diner in "Birth", the tattoo has moved about a centimeter down her wrist, and the petals have a brownish color, but in previous episodes, the petals have no color. When she touches Hook's face in the Middlemist Field in the next scene, the color is gone.
Continuity mistake: When Bossy is cutting Dreamy's beard, Dreamy asks "Who was the woman I saw?" and Bossy stops cutting, but a couple of shots later, Dreamy's beard is suddenly much shorter. (00:10:00)
Continuity mistake: There's a flashback to the life of young Pinocchio, played by brown-eyed Jakob Davies. But adult Pinocchio, Eion Bailey, has striking bright-blue eyes. It's possible that a blue-eyed child may grow up to have brown eyes, but the opposite does not happen.
Continuity mistake: When Killian Jones, a.k.a. Captain Hook, is talking to Emma on the street, he points to one of his rings and reveals that it belonged to a man who insulted him by calling him "One Hand Jones." According to Hook, he killed the man in front of his wife, and took his ring as a trophy. However, as seen in 2-04 "The Crocodile", Hook was already wearing this ring before he lost his hand to Rumplestiltskin. This is best seen while he and Milah are drinking and gambling at the tavern: In the shot of the dice landing on the table, you can see Hook's hand resting on the table, wearing the same ring.
Tallahassee - S2-E6
Continuity mistake: Sidney's newspaper article in 1-8 "Desperate Souls" stated that Emma was arrested in Worcester, Massachusetts in 1996. However, this is directly contradicted in this episode, which shows that Emma was actually arrested in Portland, eleven years before the frame story, meaning that the arrest took place in 2001 (since "Selfless, Brave and True" establishes that Emma arrived in Storybrooke in October 2011, and the frame story of "Tallahassee" takes place a few months later, in 2012; the year 2001 is confirmed in 3-22 "There's No Place Like Home"). (00:17:55)
Tallahassee - S2-E6
Continuity mistake: In the giant's treasure room, there are many giant gold coins near the skeleton of Jack the Giant Killer. The amount and position of the coins repeatedly changes. For example, when they find the skeleton, there are several coins on the edge of a small dais, but when Emma saves Hook from the trip wire, they are missing. (00:24:40)
Tallahassee - S2-E6
Continuity mistake: When Emma is arrested, she has a flower tattoo on her left wrist. When she's climbing the beanstalk with Hook, in a few shots, her wrist is bare, and you can see that the tattoo is missing; this happens, for example, when she remarks, "You should be used to people not trusting you." (00:09:10 - 00:29:30)
Continuity mistake: At Lake Nostos, when Emma is pinned down by Hook, the ground beneath her changes between shots, with regards to the markings in the sand (from the fight), as well as the amount of stones, twigs etc. (00:29:00)
Continuity mistake: When Regina is standing in front of Rumpelstiltskin's mirror at the end of the episode, as he asks, "What are you gonna do now, then?", the cloth that was used to cover the mirror is lying on the floor. When he transforms her back to her normal form, it is gone. (00:38:45)
Continuity mistake: The flashback scene where The Snow Queen takes Emma's video camera away from Kevin differs from what is seen on the video recording of that moment in "Breaking Glass" and "Family Business." For example, in the recording, Ingrid says, "We respect property in this house, Emma." In the actual scene, she says, "We respect property in this household, don't we, Kevin?"
The Thing You Love Most - S1-E2
Continuity mistake: In the beginning of the episode, as Regina stops below the clock tower and gazes at the clock, there is no sign on the blue building in the background, next to Storybrooke Country Bread. When she notices Emma's car, there is a sign on the building. (02:55:00)
Continuity mistake: When Emma arrives in town, two Storybrooke businesses, Standard Clocks and its neighbour, Modern Fashions, can be seen in a shot though a window. In the shot from above where Emma's car slows down, the name on Standard Clocks is Kaido (a real-life business in Steveston, the Canadian town which doubles as the town of Storybrooke), and there is now a white sign on Modern Fashions, which wasn't there in the first shot. (00:15:45)
Continuity mistake: The exterior shots of the buildings located across the street from Granny's Diner do not match the view seen through the front door, from inside the diner. The most obvious example is the building next to Storybrooke Country Bread, on the opposite side of the street. In the exterior shots, on the left side of the bakery, there is a blue wooden building (this can be seen, for example, when Emma is walking Henry to school in "The Thing You Love Most"), with a huge gap of approximately ten meters between the two buildings. In the interior shots where the front door of Granny's Diner is open, the view is drastically different looking: For example, when Regina enters the diner to confront Mary Margaret in "The Shepherd", when Emma brings Henry to the diner in "Welcome to Storybrooke", when Zelena enters the diner in "It's Not Easy Being Green" and when Emma comes into Granny's Diner to ask Hook out in "The Apprentice", the characters open the front door, and now there is a completely different building next to Storybrooke Country Bread. The new building seen through the doorway is made of bricks and has a completely different color, and there is no longer any gap between the two buildings; they are touching each other. Also, in some episodes, like "The Shepherd" and "7:15 AM", in the scenes inside the diner, you can see a grey wall on top of Storybrooke Country Bread. In exterior shots, there is no such wall.
Continuity mistake: At the end of the episode, the hands on the clock tower move forward for the first time. In the wide shots, the circle surrounding the clock, as well as the wooden beams forming the outer edges of the area around the clock face, are white. In the close-up where the minute hand moves, the circle and edges are brown. Also, in the wide shots, the area around the clock face of the building is shaped like a square, but in the close-up, it is in the shape of a trapezoid. The same thing happens when the clock moves in "The Thing You Love Most", "A Land Without Magic" and "Darkness on the Edge of Town." (00:41:25)
Continuity mistake: As Pan (in Henry's body) is first looking through Henry's storybook, after he turns the page, the left page is just text. Cuts to a different angle, and the same page has a big picture on it. (00:13:10)
Continuity mistake: After Emma pulls Hook out of the tub of water, the wet hair plastered to his forehead keeps changing from shot to shot. (00:11:30)
The Heart is a Lonely Hunter - S1-E7
Continuity mistake: When Graham is arguing with Emma at the beginning of the episode, in the very first shot outside Granny's, they are approaching a shop called Worthington's Haberdashery. As the shot ends, they are still a few meters away from it, but in the next shot, they are already in front of it. (00:01:50)
Continuity mistake: Emma Swan has a flower tattoo on her left wrist. It can be glimpsed during her date with Ryan, and is visible when she's sitting at the table with Mary Margaret in "The Thing You Love Most", and when she's on the phone with Ruby in "Red-Handed." However, when she opens the door for Henry in "Pilot", the tattoo is gone. The same thing happens when she unlocks the door to her room at the inn in "The Thing You Love Most" (in the scene where she is evicted), and when she's pressing a pack of ice against her wound in "The Heart is a Lonely Hunter."
Continuity mistake: When Mr. Gold and Belle are walking to the pawnshop together, their position in relation to the storefronts they walk past keeps changing. Most notably, they walk past a couple of wheelbarrows three times in consecutive shots. (00:13:35)
Answer: He knows who she is because he knows that the fairy tales are true. He was also shown to sneak out to go see Emma or someone else. Sometimes he succeeded, sometimes he didn't. This is how he knew to look for her despite his strict mother.