When Ellie gets a call from Jason while sitting at her desk, the picture frame with the drawing he sent her is standing right in front of her. In the next shot the frame is gone.
When Ellie gives Jason back the key to their secret garden the ribbon is wrapped around the top of the key. In the next frame, the ribbon has unraveled and is dangling from the top.
When Jason is on his way home from his date with Ellie he calls Mikey and ask if he is home. Mikey than ask how it went with the "hooker" and Jason goes onto explain. The next morning when Mikey comes home and burst into Jason's room he asked again "How did things go with the hooker?" But he already should have known from his phone conversation the night before, so there was no reason for him to bust into the bedroom.