For me personally, Realism tends to be my anchor when creating any set of characters in my stories. I forget about trying to fill "archetypes" and instead just focus on creating a character with a distinct set of traits and personalities that fill the role I want to be done. If anything, personality comes second. In my experience, role comes first in the creation of a character. There's nothing more distracting than a character whose entire existence is just to be there.
Say you want a detective... you start with just a silhouette of a detective. Nothing much to it, just a blank canvas of a detective. They detect things. Yatta yatta yatta... now you have to look in the context of the story. Why do you want a detective? What role are they trying to fulfill? Let's assume that for the sake of this example, this is a typical crime story, and that the main focus here is the detective. Now there are two common ways to go about this story (although there are variations, I won't go over them for this) either this is a rookie-to-superstar type or a grizzled-vet-meets-challenge type story. If the story's about progressing through the ranks, then a younger person would be more suitable than an old one. If it's the other, than vice versa. You start filling in the "holes" as you go about exploring your story and scenario, as I'd like to say. Is this person on their own, or are they still learning the ropes? If they're still learning, then they probably have a mentor to guide them. What about the case itself? Is it a small one or is it one the police has put a lot of strain on? If it's the latter, the department would probably assign skilled detectives to that case. You keep going, jotting down whatever comes to mind about the story's scenario and what this person is intended to do, until there is a solid base underneath this character to work on. Personality is secondary.
I find that personality isn't meant to stand alone in the face of the entire story. It's merely a complement to whatever role that character happens to be fulfilling at that moment. A cheerful girl simply is not as interesting or useful as a flowergirl, and it leaves the character rather stranded in the abyss with no real purpose to grow the story. Looking on the outside, you can more-and-less see yourself as a "hiring manager" of sorts. There are occupations your story needs in order for the plot to run well, and it is your job to fill these roles with the necessary people in order for things to work. Depending on who you choose to fulfill the role, things can progress quite differently. A strict sword-smith would probably outright decline the hero trying to buy his wares than a laid-back one. A reckless friend is more likely to get the protagonist into trouble than a caring one. There are other methods to building characters, but this is one I tend to abide by. Remember, you're not looking to hire "the self-righteous guy" or the "cunning girl" or the "squeamish prick", you're hiring "the lone adventurer", "the rogue assassin", the "bookworm", people who have occupations, not personality. Personality is the cream of the crop, but it should not be mistaken as the basis for good characters. Without a good foundation, characters will crumble to the ground against hefty pressure, particularly in the face of the story's complex plot and setting.