1) No explicit monster face, though their eyes may get weird and predatory looking, may turn red, and yes, all of their body fluids are blood.

2) No heartbeat.

3) Cold, hard to cut skin.

4) Fangs that can get even bigger if they are amping up for the kill.

5) Longer than normal tongues.

6) Finger nails that are hard to break and claw-like.

7) Consumed blood isn't proportionate to how much blood stays in the body. (IE they can drink a lot more than a body could hold.)

8) Burn in sunlight, though it would take a bit of exposure to actually die.

9) Genitals are still functional, with some effort.

10) Usually vampires become more attractive, in subtle ways.

RE: SNAKES - yes, they would require far less blood than a human sized vampire.