When Laura leaves the hotel near the end to pursue John, she is wearing boots but is barelegged. Later in the chase as she scrambles over a boat, she is wearing the same boots but is now also wearing dark colored stockings/tights.
When John sets Laura off on the boat, just before she enters the boat they hug and kiss and the camera is on the inside of the boat filming them while they're on the pier. The next shot is the same shot all over again only from the different angle (now the camera is on the pier as well). Although they had just hugged and kissed they did it once more, filmed from a different angle.
When John climbs the scaffold, the camera follows him from the priest and up to the top of the church and he has gloves on the entire way. However, when the camera briefly switches from him to the workers below and back to him, his gloves are gone and do not return for the rest of the scene.
When Laura enters the hotel and finds the two sisters by the end of the film, she's holding her coat. Then she gets immediately warned to run after John because he is in danger. On the next, when she rushes down the stairs, she doesn't hold a coat any more.
In the bathroom scene, John Baxter steps over Laura's clothes, piled on the floor. Among them is a pair of tights, which she was clearly not wearing in the preceding scene (in which she undresses).
The dead woman that is hauled up from the river blinks.
When "Laura" (Julie Christie) is boarding the river boat, the camera dolly is visible, reflected in the windows.