There are really two main parts to personality, a collection of what they are and how you know, and you use these to determine they interact with the world. They are (what) brooding and you know that (how) because they are always on their own. They are (what) bubbly and vibrant (how) because they are wearing bright colours and always smiling.
Sometimes it’s easiest to start with a trope or archetype, such as the brooding loner or that bubbly sunshine character, and adjust that character into something that will work better for your story.
There’s one main thing to remember when it comes to a character’s personality.
Show don’t tell.
I know, we’ve all heard it before, but that is imperative for personality more so than any other aspect of the character that you show the audience what they are like more than you tell the audience what they are like.
To do this, we’ll go through the first impression, how a friend perceives them, what the character thinks of themselves, and what you, as the creator of this character, know to be true. This could all be the same, but it often isn’t. This is where some of that depth and dimension comes in, from knowing that different people might interpret differently a character’s actions.
I will start off with an example of how I, an actual person, have been interpreted in the past. I went down to the States to visit friends and while at a store to pick up a couple of things. When I handed the cashier some cash and told them to keep the change.
To the cashier who had never met me before and would never see me again, I was probably stupid because it’s common knowledge that you can’t keep the change at a store like that. I was likely also apologetic and chatty because not only did I keep apologizing, but I also had a brief exchange with the person behind me in line to apologize and ask where she got her earrings.
To my friends, I was generous and respectful because I was trying to tip the cashier, as they believed I, as a Canadian, thought it was customary to tip all low-wage employees in the United States and they had been watching me apologize like it’s an accent the whole trip so far.
And to me, I was nervous because I was overly aware of the line behind me and also polite because I had inconvenienced someone.
The truth of it is that I was anxious because I talk when I’m anxious and tend to change the subject to the first thing I can think of (The earrings) to get the attention off of the thing I did.
Plus, there were pennies in the change. I can’t use those back home. It would have been easier for them to keep it.