Make a list of questions you could ask your character, or look for a list online. Then, go through the list and answer each question as your character. Base the answers on your character’s background, their personality, and what they want.  Questions might include, “What’s your favorite food?” “Do you have a pet?” “What is your relationship like with your family?” “Where do you see yourself in 5 years?” “What is your earliest memory?” “What is your dream job?” “Who is your most trusted confidant?” and “What’s in your bedroom?” As an example, Alice might say that her favorite food is homemade kettle corn because she likes the salty-sweet taste. She might also say that she has a black cat and an orange cat that act as her familiars. Give your character an accent or speech pattern that shows their background or personality. Additionally, use words and sentence structures that reflect your character's level of education and place in society. This will help your audience learn more about your character through their speech. As an example, Alice might include old fashioned words in her speech and may occasionally rhyme due to her experience making spells. She might say things like, "The forest has darkened a wee bit early, but that's no reason for you to get surly." You can learn a lot from a person by watching how they go about their life. This includes activities like cooking, eating, cleaning, driving a car, or talking to a receptionist. Explore how your character acts in these moments to help their character development.  For instance, Alice might clean her house and cook her breakfast using a spell. Then, you might have her struggle to purchase items at a store because she can’t use her magic there. This shows that she overly relies on her magic. As another example, you might show Alice trying to check out a magic book from the library. She might blush and mumble when she talks to the clerk and have trouble making eye contact. This shows that she’s shy. Real people have opinions, so your character should, as well. Consider which issues in your story will be most important to your character. Then, decide what your character’s opinion on that issue would be. Use this opinion to help with character development. For instance, Alice might believe that witches should live separately from non-magical humans. This might make it hard for her to work with humans. Additionally, it might create conflict between her and other witches. Show your character interacting with their family, friends, or an antagonist. Make sure that each character is distinctive so that you see the similarities and differences between them. This helps you better understand what your OC is about and who they really are. As an example, let’s say Alice has a best friend named Trixy. You might have a scene where Alice and Trixy come across an injured witch in the woods. Alice might stop and help the witch, offering him her last bit of water and food. Trixy might roll her eyes and tell Alice that she’s wasting her time by helping. Then, Trixy might go to get help but return really late because she took a break to do something fun. This shows that Alice is kind and helpful, while Trixy might be unreliable. To make your story interesting, you have to give your character problems and deny them what they want. Create obstacles and losses for your character that keeps them striving to get what they want. This helps them develop as a character and keeps your audience rooting for the character. For example, Alice might almost find her parents but them they get moved again. Similarly, she might realize that her best friend Trixy is secretly helping the person who took her parents.
Ask your character questions to create character development. Create a unique voice that reflects your character's persona. Show your character in everyday situations to portray their personality. Make your character take a stance on an important issue. Develop your character’s relationship with other characters in the story. Take something away from your character to build tension.