Although the characteristics of vampires vary depending on who you are listening to or what legend / myth you are reading from, there are some traits that seem to carry over from legend to legend or story to story.  The most common / typical vampire characteristics include the following:

Fangs
Almost all vampires are depicted with this characteristic – very sharp, long fangs. Vampire fangs are intended to help them with the their eating habits (see next vampire characteristic).

Drink blood
This is one of the vampire characteristics that is universal among all vampires. Vampires are known to live by drinking blood. They do not – and cannot – eat regular food.

Extremely pale
Vampires are known for being extremely pale. It is said once they have “eaten” (see vampire characteristic #2) they can appear flushed, but at almost all other times they have alabaster white skin.

Extremely strong
It is said that vampires are practically invincible – their skin is said to be tough as stone.  It is also said that they have an inordinate amount of strength.

Active only at night / Cannot be exposed to sunlight
This is another of the vampire characteristics that is pretty universal among all vampires – it is said that sun burns their skin.  They therefore cannot be exposed to sunlight.  It is one of the few things that will destroy a vampire.  Some modern tellings and stories of vampires however claim that this is not necessarily true, and is myth rather than fact.

Shapeshifting abilities
While shapeshifting is most traditionally believed to be one of the characteristics of the werewolf, there are some vampires that are said to possess this ability.  Most commonly it is said they can shapeshift into smoke or bats.  This is another of the vampire characteristics that is under some controversy.

No reflections
In traditional stories of vampires, you can tell if someone is a vampire by whether or not they have a reflection.  It is said they cannot see themselves in mirrors.

Sleep in coffins
This is one of the vampire characteristics that is true in stories but not in actuality.  In stories it is said that vampires sleep in coffins during the daytime, and come out at night.  Dracula is the prime example of this type of behavior.  Almost all modern stories of vampires claim that this is in fact not true of all vampires.

This is not a comprehensive list of all vampire characteristics, but rather some of the more common ones.  Most modern real vampires claim that not all of these apply to them. This may very well be true. As werewolves can tell you, not necessarily every werewolf is the same. The same is likely to be true with vampires as well.