Adopt a non-cliche'd Vampire trait.

Okay so there are sooooo many vampire stories, and I'm working to NOT make mine really boring and the same as every other one that has been written since forever.
So go ahead and post variations on preconceived vampire traits (burns in the sun, drinks blood, transformation strategies, has to be invited in etc. etc. etc.)
Leaving: The beginnings of vampires are created by a chemical (used in a lab or a war or however you want to introduce the chemical), some individuals are affected by accidental use of the chemical which unbeknownst to them causes a blood disease with the symptoms of vampirism (sun issues, etc.)

Leaving: Vampires actually created sunscreen for obvious reasons, but ended up making their vast fortunes on the sun block industry.

Vampires can actually get AIDS. Of course, since they have weakened immune systems and can't die, they simply get really sick forever.

(Last year I did a vampire novel and I had a character who was always in a sour mood because he was always so sick. XD If a human ever made fun of him for it, he'd kill 'em.)

When you first turn into a vampire (and maybe even for the rest of your vampiric life), you start having detailed visions of mercilessly murdering everyone in the room. And possibly torture and other violent things too. These visions can only be stopped by drinking blood.

( It works as a nice excuse to write some gory scenes with one character killing all of the others only to realize that nothing actually happened. And it gave my nice-guy MC some serious inner conflict as he realized that he suddenly wanted to kill everyone...)

Ithink I might take the sunscreen one XD

Leaving: when you first become a vampire you have very strange dreams (You decide on the dream!)

When you first become a vampire your bones feel like glass

When you're a vampire, your abilities depend on another vampire to be sustained. It takes an emotional bond which intrinsically connects two vamps and keeps them faster, stronger, and blood thirsty. Otherwise, the vamps have the ability to re-mortalize after half a century.

Those are the characteristics I am using this year in mine :)

When a vampires makes another vampire he or she has the ability to have complete control over the new vampire, if he or she so chooses. Therefore, the new vampire could potentially have no will of their own, and have no idea what he or she is doing or any control of their own actions.

That's what I'm going with. ;)

Traditionally speaking, vampires have no problem with sunlight. It was only in F.W. Murnau's film Nosferatu that Count Orlok was destroyed by sunlight and, as the film became so iconic, the legend stuck.

Vampires are, however very obsessive-compulsive. The easiest way to stop a vampire in its tracks is to throw rice or seeds at it. They have to stop and count every grain.

I'm using the obsessive-compulsive thing in my story. My character carries around a baggie of rice in her purse in case she's attacked. It can also make for humour because i'm planing on having a purse break and the baggie explode while her vampire boyfriend is around...

btw might take the sun screen one. That's pretty epic :P

Also, there is a real disease that mirrors vampirism. I did a presentation on it after learning about it through CSI of all places. It's called poryphoria - people with it are extremely sensitive to sunlight (they tend to get boils and miscellaneous types of abrasions upon extended contact). Something about the tissue of their mouths/gums is mutated so the skin around the mouth tightens and shrinks, which makes canines ("fangs") more pronounced. And, naturally, garlic makes their symptoms even worse due to sensitivity. And apparently their pee is purple and red... And also whatever imbalances their body has can affect their brain; it can lead to depressions and peculiar behaviour.
So you could have a character who everyone BELIEVES is a vampire, or a character that BELIEVES they're a vampire, but is really just a poryphoric.

Anyways...

* all mirrors break in the presence of a vampire. Or anything reflective (i.e., windows... can make for some fun if glass slices humans and the vampire has issues controlling themselves :P)
* this actually isn't mine but it's worth sharing (originally from Wizards of Waverly Place) - vampires are actually repulsed by PUMPKINS. Halloween is torture for them because of this.
* they're pyromaniacs. Always setting fires.
* anyone read Shiver? The "werewolves" in that story turn due to temperature change. Twist that into something like while vampires can wander day and night, only a certain time of day (take your pick - are they an early bird - 6am til 9am? night owl - 9pm to 2am? specifically between 11am and 3pm?) are they ravenous for blood and only drink blood at that time of day. Whether or not they're adversely affected by drinking at times other than between whatever you allot can be up to you.

A human nine times out of ten hates the vampire who turned him/her and will try to kill them.

Umm...how about whenever a vampire drinks a lot of blood, they become extremely bloated for a few days. Kind of like how salt retains water. Cue emotional vampires who are upset about how they look.

Vampires, in fact, have black blood (hence the pale/grey look they have, as it is our blood etc that makes us pinky)
They cannot make their own supply of blood, therefore have to take it from a human
Their own blood contains 'pigments' which stem from their heart, and 'stain' normal blood, turning it into black, vampirical blood
A person becomes a vampire when they are injected with vampire blood, which 'stains' their heart, and therefore forcing their own heart to produce 'pigments'
a vampire can be cured via a heart and lung transplant, and complete replacement of all their blood (which is pretty much impossible)

not sure if I explained that all that well... and it might be a bit naff now, came up with the 'staining' idea a couple of years ago...

So stealing this one, its great and fit in with my story so well

"When you first turn into a vampire (and maybe even for the rest of your vampiric life), you start having detailed visions of mercilessly murdering everyone in the room. And possibly torture and other violent things too. These visions can only be stopped by drinking blood"

I'll leave the concept that I'm using which is they hate lemons. Its from folklore that a lemon was placed in the mouth of suspected vampire corpses and i think its pretty cool, takes a new tiwst on the garlic anyway lol

Cats can tell if someone is a vampire, and like to follow vampires around, just to annoy them. And vampires hate cats.

The one I'm using, and you can go for it, or adapt it, is:
The older a vampire is, the crazier he is (making for some really twisted, powerful vampires). The ones that are, say, under a thousand years old (or whatever you like) are still human enough to interact with. Thus, the powerful vamps make the new vamps, but it is the middle-aged vamps who "tutor" the newbies, teach them to control their thirst for blood so they're not constantly rampaging, teach them about whatever powers they have, etc.

I also based mine off of Dracula, who could totally wander around during the day, but didn't have access to his powers then. So they prefer night, but can transact business during the day. (You know, go to the bank to cash their massive sun-tan selling check.)

However, my main characters are Mexican and Filipino, so the Filipino ladies call them aswangs (a Filipino ghoul fairly similar to vampires), and I haven't yet found a good Mexican variant ... and so far, the vampires haven't referred to themselves as anything. I'm not sure if they ever will ....

My theory is that vampires can drink alcohol to an extent because liquor mixes well with blood. However, since vampires have SUCH a slow metabolism, hangovers can be a serious problem.
Line: Human, "So, you drank yourself into oblivion for the first few decades."
Vampire: "Well, I had wrapped my head around my situation, so that I was doing all right with that. Mostly I just didn't want to come off the drink."
Human: "Why?"
Vampire: "Have you ever had a three month hangover headache? Yeah, didn't think so."

If you have half vampires, they have all of the disadvantages and none of the advantages. (This was actually the NaNo plot I used in 2009, and it was really fun!)

I also once wrote a short story where technology had enabled vampires to create a liquid that sustained them just as well as human blood did. The trouble was human blood was pretty crazy addictive. Thus there were two camps of vampires, those who took the alternative and were trying to get along in a world of mostly mortals, and those who were crazy, desperate addicts who frequently killed to feed (as they just couldn't stop themselves).

Vampires are normal humans until they see/smell/taste blood, at which point they go vampiric.

Vampires are not in fact vampires- they are in fact albinos (pale and issues with sunlight, because albinos burn straightaway even with suncream) who are just particularly athletic and drink blood for a reason that you can make up.

Some Vampires can smell different blood types, and consider themselves connoisseurs, only choosing to go after people with rare blood types.

(One I'm using in my side project) The blood of someone high on drugs contains a trace of the 'high' and is addictive in itself. In fact, some Vampires create 'junk farms', where several addicts are kept on a permanent high so that their intoxicating blood can be harvested.

Other Vampires eschew blood in its entirety, choosing instead to drink coconut milk, which was used as a blood plasma substitute in the Pacific theatre of operations during World War II.

Not sure if this counts, but I once had a story where the vampires were actually supposed to kill humans, to keep the population in check, & the humans would hunt the vampires to keep them in check... It was a cycle, meant to keep them in balance.