When Karen falls down the stairs after striking Doob and is laying on the floor we see him walking down the stairs after her with his cross on the outside of his shirt, in the next scene when she shoots him, the cross is back inside his shirt.
When Meghan is in Julie's room eating an ice cream and accidentally drops it on Julie's pillow she smears it in while trying to wipe it clean, but in the next shot when Meghan attempts to hide the accident from the nanny the ice cream is in a glob again.
In the other rape scene in the film, the Spanish woman is being assaulted on the table. When Kiefer Sutherland flips her over and she is facing down, the camera breaks to a different point of view and in the mirror reflection, she is clearly on her back again, legs kicking in the air. Then with another cutback she prone, face down on the table.
Karen tricks Doob into thinking she's in the shower by draping a towel over a bar. However, when he pushes the door back into the bathroom someone is clearly behind the shower curtain as you can see their back arch and then dip their head.
In the rape scene you can see Julie wearing a flesh colored leotard.
When her daughter practicing French correctly says, "Sur la table," Karen "corrects" her, insisting on, "Sur le table." This however is wrong and her daughter had been right the first time.
When Karen McCann (Sally Field) requests Robert Doob's (Kiefer Sutherland's) police report, the clerk whites-out Doob's address from the Xeroxed copy, then gives that same paper to McCann. That would never be done, since the blocked words could be read through the paper from the back of the photocopy. Any real records clerk would re-Xerox the altered record and give McCann the secondary duplicate, from which the blocked address could not be read - either from the back of the paper, or by wiping the front of it (as McCann was doing).
The FBI does not normally involve itself in local jurisdiction crimes unless the perpetrator(s) have crossed state lines.
When Doob's second victim is lying dead on the table, as one of the cops walks pass her you can see her blinking.
In the scene right before Karen screams about the pillow being washed, the little girl and her father are sitting at the table eating breakfast. The little girl tells her father that she doesn't like bananas. You can clearly tell that the little girl messed up and said something else causing her to laugh and break out of character.
When a closeup shot is taken of Doob's dead body, there appears to be a pulsing in his neck.
When Karen is following Doob as he makes deliveries she begins to pull over her car before he does.
In the opening bathroom scene, reflected in the convex mirror that Karen bumps.
A crew member is reflected in Megan's bedroom mirror when Karen runs in to check on her.