In the opening sequence, the front license plate worn by the green Jeep isn't even trying to look like a real plate. There is a "bite" taken out of the lower left corner, something impossible to do with a metal plate, and there are no lower mounting holes on the plate.
The revolver Kensi shoots at the firing range is obviously a five shot gun, yet she squeezes out six shots in quick succession.
When Mike Renko is shot by the sniper, the sound is heard before he is struck by the bullet. Bullets from sniper rifles travel much faster than the speed of sound, so he should be struck before the sound is heard.