Creating original characters is, at least for me, fundamentally very easy: I've read too much, known such a large number of different people from such disparate walks of life (including different countries, 'social classes', what-have-you), to say nothing of all the garbage rattling around my dark and dusty mind that I've always got ample material to create fictional characters, no problem.
Creating original, INTERESTING characters is another story entirely: I am capable of doing so, and have done so (and will likely continue doing so, at least until my mind gives out entirely), though I don't see it as easy or difficult (it's both); and for a writer of fiction -- aka 'a storyteller' or less euphemistically a 'liar' -- it's a bit of a must, as writing about boring characters is, well...Boring. And who'd ever want to read it?
I suppose one of the benefits/hazards of having led an interesting life is (at least for a fiction writer) that it renders most of the characters one could think of sometimes rather tame, in comparison; of course, this, in turn, forces one to populate one's mind (and writing) with characters who are 'over the top', as it were; riddled with flaws which even I would check myself into a psychiatric facility over, people who have strange beginnings and (sometimes) horrifying ends...
And, well, to be entirely honest, I don't know how some of the characters I've created truly came about, so, like Poe's explanation for how he wrote The Raven (which no one, to the best of my knowledge, actually *believes* is how he wrote it, being merely a dissertation using logic to serve as a footpath for his true creative genius which he couldn't name), this particular essay of mine is bound to be just as disappointing (more so, given it wasn't penned by Poe :D).
I can say my favorite (and, I think, most interesting) characters come to me either entirely or mostly fully-formed, leaving very little for my conscious mind to do; therefore, I cannot give anyone much advice as to the creation of characters.
Of those which are not 100% formed, I've found that writing a few pages as that character quickly fleshes them out; one time I dashed off at least 10-12 thousand words which was merely a conversation between two characters, the writing of which revealed to *me* more about them than would ever appear in any story.
I suppose one thing I can say is when creating a character, know *everything* about them. I can think of one character I created who (partially) survived the Great Famine in Ireland in the 1840s by resorting to cannibalism; I can also tell you about his relationship with his parents, when he first kissed a girl, and who he had a crush on, though (almost) none of those things are even remotely pertinent to the story he is in, and therefore won't ever appear in writing.
I have another character I could easily write a book solely about (actually, I have a number), including his innate acrophilia, which led him to fly an Albatross for the Luftstreitkräfte in WWI, and (while never an Überkanonen, given his avoidance of combat wherever possible) his eventual ditching of that particular make (either a BII or CII -- my mind dims with age, obviously) only to fake his own death and pop up flying a Sopwith Camel for the opposing side -- and not because he had any desire to shoot anyone down, really gave a shit about who won or which side was 'right', nor was he eager to engage in aerial combat -- merely because he wished so very badly to be able to *fly*, and went to what would be, to any sane person, incredible and dangerous lengths to do so (particularly given that period of time). That little to none of the above information appears in writing connected with him is...What it is.
My point -- were I to have one, which I'm certain anyone reading this drivel would argue vehemently against -- is that, to make *real* characters, they must be real to the *writer*, first and foremost.
'If you're writing in the first person, you must be that person' and all that jazz. Obviously, if one is writing a story and one has two-dimensional characters, the reader will sense this *immediately* -- I know I have -- and when one has created compelling, interesting characters, that can make for an enjoyable read, even if the plot isn't as good as it should be (even if only from a purely Aristotelian perspective), while the reverse is not true: even the best plot will put most people to sleep if the characters are trite knockoffs/boring/garbage.
Perhaps the 'secret' to creating compelling characters, fully clothed, born in one's mind as complete and whole as Athena was when she sprang from the forehead of Zeus, is to have an overly full mind ;)
