Near the beginning of the film, Lynn is given a handful of cigarettes, which she sort of refuses by putting them down on a table in a jumbled pile. When next seen, they are in a neat, aligned stack - making them easier to be picked up and placed back in the box.
At about 07:45 when there is a close-up of Gregory Ratoff (Vinmont), "Sol" is behind him without his beret, whereas in the preceding shot and the one after he is wearing a beret.
When Lynn is working late, as she leaves Tom to bring the unfinished report to Mr. Dwight, the moving shadow of the boom mic is clearly visible on the wall by the door.