Jonathan Harker's shaving mirror, while it is hanging on the wall, is clearly made up of one large central panel and four beveled panels at the edges. However, when Dracula takes it and waves his hand over it, it consists of only one large, flat panel.
When Renfield grabs the bars of his padded cell we can see that they wobble and are clearly made of rubber.
The shaving mirror scene: when Harker moves, there is a slight but noticeable delay, with his reflection moving just before he does. This occurs a few times, and makes it obvious that a trick mirror (possibly a Chromakey screen) is being used.
When Lucy is in her coffin her eye-lids flutter and her face moves.
During the opening scenes of Harker taking a train into Romania, the stock footage appears to be taken from an American western film, showing open desert and prairies. This in no way resembles the actual countryside of Southeastern Europe, which is heavily forested with hills and mountains.