Attention, class. We covered plot yesterday, so today let us move onto the helpless dolls and puppets in your story that face horrors and fantasies... I mean, uh, *cough* your characters!
The definition of "characters" in my English class was blunt as well, sadly. To quote our test, characters are "persons who are given personalities and role in stories". True...and false.
For the truth, I would certainly hope your character have personlity. Traits, habits, manners of speaking, and experience are just some of the makeup you give them. Characters are like us - maybe they have the same taste in music as whatshisname, and dress like that-one-girl, but everyone manages to be different and unique.
Good characters are when they might do something, or say something, and make us think, "that's so him/her". It means you put a clear image of the character in the mind of the audience. So know your character well. I can honestly say I know most of mine better than myself...well, on good days.
The false part is the "given roles". Hello. Stories are not waiting for actors to portray them. It is the characters, and their back stories as well as a variety of their own habits and traits, that truly begins a story. Usually, tales are centered around relationships, or a decision the character makes. How can you just insert a random person into this plot, and not expect it to change?
If you really want characters to stand out, don't create a story then throw them in. Create them, and let the story fold around their own quirks and oddities.
Be sure to remember...are you the same as you were ten years ago? Yeah, I didn't think so. Not that I can say much...ten years ago I couldn't spell 95% of the words in this blog post (I was five, hahaha). We're all characters. If you put that in mind, you should be good.