Well, when you're creating characters I think it's best to think about your friends -- each and every one of them. What makes them different? When they speak, how do they talk? Do they have any weird ticks/quirks/habits? Body language is also something to look into. Think about how they'd react in a certain situation. People are not all the same; we're different in sometimes just the slightest of ways. Listen to people interact around you for a day or two.

If you're writing an idol, watch their shows and take note of how they act and what they've said about themselves/members have said about them! Even reading interviews is a good idea!

I agree with dream_keeper88 about making a character sheet. Just for yourself. Asking yourself questions about your characters and answering them can also help you out! Good luck anon & everyone else who struggles with this!

Well, working with more than three characters is difficult enough for me since I have to give them separate voices. Anyway, as the others suggested, observe people around you and design your characters based on them.

Here in AFF, most find it easy to write stories with multiple characters, because they write members of a real kpop group. Just watch their interviews and reality show where they appeared. Read magazine interviews. By watching them, you'll have an idea what kind of person the artist is. Their habits, mannerisms, likes, etc.

Since you are dealing with multiple characters, I also suggest you take time to fill up a character information sheet. There are templates available online or you could make your own, like a personal data sheet. This is for your reference only. Posting it in the foreword is a turn off for me personally.

I hope that helps.

Most of the time, I just make it up as I go along. But, if I'm having trouble defining a character, I sometimes sit down and create a back story for them. For example: write down where they were born, what their childhood was like, have they had any traumas..., and so on. Then, when you go to write the story you can explain why the character acts the way they do. I hope that helped?

Hmmmm well sometimes when I create my characters, I try to create their personality's from the people around me ^^ When I talk with some family members or friends I look at their personality and sometimes use their personality for my character's. I'm sorry if this made no sense what so ever, I'm terrible at giving advice here *chuckles sheepishly* But good luck to you anon <3

Then, there's the last one, maybe he has a bad record at school or his university or overall and if he gets one more strike, he's done (maybe one of his parents did something similar and the emotional trauma and scars has left him feeling utterly scared of the idea of ever committing a crime). The situation he is in (almost hitting the OC with his car) and the way he reacts to it shape him in the story and to the readers of the story. So, there's no problem with using a Mary Sue, it's just that it depends on how you use them. How they interact with the story as a whole. How do other characters interact with the story as a whole as well as the situations they are in that make up the story? That's their character. That's what I focus on anyway.

Okay, okay, okay, I've read bits and pieces of the other responses on here and there is something I have to disagree with. Don't make a character a Mary Sue? Why not? Mary Sues are typical and cliche and boring, sure, but it is still a character type. There's the bad boy, the good guy, the wise guy, the smart girl, the Mary Sue, and the list goes on. So, what's wrong with having a Mary Sue? What's wrong with having that cliche character in your character roster? (Nothing, that's what!)

So your story has more than ten characters, what should you do? Base them off of real people? You could do that. Or, you could simply base them off of the situation they are in. A person is made up by what they experience and how they react to these experiences. Say you have your OC almost get hit by a car being driven by one of the male love interests (let's call him MLI). Does MLI act like a jerk about it and care more about his car or does he genuinely feel sorry for what he's done or does he freak out about going to jail if he had hit the OC? If he's the first, then he's materialistic, most likely grew up with either richer parents who provided him with everything or poorer parents who valued the money they made over the people they interacted with to get it (that's for you to decide). If he's the second, he's the nice guy, the normal guy, who feels bad but does he still drive off with the intent to never see the OC again or does he offer to take her to where she's going or buy her something to compensate for almost taking her life (and does he do this because he thinks a human life can be bought or because he simply doesn't know what else he can do to make up for it because there's simply nothing he can do to compensate for the OC's life almost being taken?). [Continued in above comment.]

lol like the author below me said. As long as they don't make mary Sue, they're different xD but this is honestly a good question. I'm only a reader so...I don't know

I have a story with around 37 unique characters. Like everyone below said, if you can't think of anything, base them off people you know in real life (I did this a few times but then stopped cause it started getting awkward when the romance started).

You can always do character interviews, bios, profiles (not those bland 'cute, sarcastic, smart' ones. Go into DETAIL. What do they wear, how do they talk, what are some words they use often, how would they react if this happened, parents, home life, small habits, etc etc. Everyone is different in those aspects. Remember that characters [people] are always three dimensional and layered. What you see on the outside isn't always what's on the inside.

No matter what, just don't make a Mary Sue...

Like the user below said, it's important to pay attention to the people around you or even just a random stranger who happens to take the same train as you one day. Think about what this person might be thinking, what kind of traits he/she might have... mostly, know your character. Maybe you feel this is crazy, but pretending you know your character in real life, or even that you ARE your character would help a lot in understanding how he/she would react in situations etc.

Well, I usually base them with people I know and I interact with on a daily basis.
EG. Friends, family, classmates, teachers, and etc :)
It's easier to base them with a real life person whom you really know than to create 10+ personalities ^^