Strangely enough I tend to kill a lot of people in my stories - maybe to prevent sequels. But seriously: I've written crime stories ever since I started writing (I was about 13 then) - and what can I say ... most of them are about murder. I've plotted two crime stories (although currently I'm not working on them) and one ends with the villainess dying in a truly gruesome way while the other has a host of different murders (everything from hanging someone right down to poisoning).
When I was younger, I had serious problems with killing off my characters, but that has changed a lot over the years. I love my characters, it's just ... well ... I love killing them, too. They are mine, after all. I have created them and so it's my privilege to destroy them when I want to. (That bears the question how God thinks about that sort of thing, doesn't it? Be grateful I'm not God, though, or you might suddenly find yourselves trapped in a pit with a hungry hyena or something.)
Ever since I dabbed into other genres, I had to learn how to do good action scenes (you try writing fantasy without a few sword fights...), how to describe landscapes people can't just google ('cause they're not in this world) and other useful stuff. And I had to learn how to do a good murder- or dying-scene without overdoing it or skirting over the important bits. I don't describe in detail where all the little splashes of blood land - go and watch CSI if you're interested in that sort of thing -, but I don't just write "and then he was shot" either. That would be pointless, because the police will later on claim "he's been shot" anyway. Instead I describe the situation.
For that "Harry Potter" dystopia I had to do two dying scenes already. I had a man burned (and that's a gruesome way to die, I know - let's say, he had some help in avoiding most of the pain, okay ... because I like him). And I had a traitor executed by the character he betrayed. After I wrote it and read it for the first time (it's different while you write it - for me, at least), I was very surprised - in a positive way. Who would have thought I could write such a scene from the victims point of view? It worked perfectly and allowed me to portrait one of my main character in a new way (God, she can be so ruthless ... and she should be, sometimes). (Oh, actually, I have to admit that there are a few more deaths, but they aren't worked out that well. Just two people and a unicorn dying quickly.) Talk about death rates in my work ... or rather: Don't!
Have you ever (and that's not off topic here) realized how dangerous it was in "Star Trek" for an unknown character in a red shirt to speak? A comedian I like very much used to do a little joke on that fact for quite some time. Wear a red shirt and say a word in a "Star Trek" episode and you won't live to see the end of it.
Well, with my stories, there's no such thing as easily recognizable mark for those destined to die. I can (and I have done it) write a story about a hero going forth to kill the villain - and then have the hero die slowly in the end. Every character that walks into my stories must be prepared to die - any time, any way. (And yes, I know I need help...)
That's probably why I wanted Harry Potter to die at the end of the last book (whether he does or not I won't comment on right now - I know the answer, if you want to know it, read the book). Killing your hero in the end means making a clean cut. He's dead, so there won't be another story with him (unless, of course, I really need him and pay a necromancer handsomely for some "return from the dead" spell [Richard from "Looking for Group" for preference...]).
So you have been warned: Never get into one of my stories as a character - unless you want to die anyway!