Palmer's red tie changes between shots right after he puts it on.
Gaines' monitor image (and our POV) of Nina apparently lying dead appears to come from a hand held camera from someone walking up behind or to the side of Jack as he shoots her. Even though there does seem to be one in the thugs' car, neither of them get out of the car, and, even if they had used the camera, the POV shots don't match up to what they can see while seated in the car. There's no way they could view over the embankment, where Nina lands.
The sun is just rising above the horizon in the beginning of the episode. However, when Jack stops at the traffic lights all shadows show the sun standing high in the sky, revealing that the episode was filmed in broad daylight and that the dark look has been accomplished by post-processing.
Kevin tells Teri that Kimberly will die if he doesn't bring her to Gaines in a half hour. He's been conked out, he just came to, and his hands are tied behind his back. Since his watch is presumably on one of his wrists, how does he know what time it is?
When Kevin gets the message from Gaines on his cell phone, we see him take the keys out of the ignition. When he gets out of the car, you hear the ring that usually tells you that you left the key in the car.
Wearing an earpiece, Jack Bauer at CTU hears instructions to shred the piece of paper on which he has just written a note (at 0:15:10). He then puts the paper into a paper shredder that does only vertical cuts. That would be a common home shredder. CTU would have specialized shredders that added - at least - horizontal cuts to the vertical ones. That security special feature makes reassembly of shredded paper more difficult to re-assemble into a readable page.
When Kim pushes Rick away telling him to get off of her a crew member holding some measuring device can be seen for a second in the lower right corner.
As Jack takes Nina out of CTU they walk to the car you can see a crew member standing in the parking lot for a brief second.
(at around 29 mins) The leg of the tripod is in the shot while Teri is trying to get a cell phone signal. (Bottom Left)
Rick and Kim Bauer are planning an escape using chalk on the ground someone approaches - Kim pulls Rick down on top of her to pretend Rick is attacking her so that they are not discovered. Kim then kicks Rick off of her - as he backs up you can see a hand in the right side of the screen holding some sort of clipboard with LCD numbers on it. A few minutes later in the same scene after the bad guy leaves and Rick comes back toward Kim there is an arm/hand visible on the left side of the screen.