Your character's appearance will be partially influenced by genetics, and partially by their personality. They will choose hair, piercings, clothes, and accessories.   For example, a shy girl might have long hair that hides her face, while a practical girl might prefer short hair that is easy to wash. Try doodling your character (even if you aren't good at art) to help you imagine them and how they might look. How much wisdom and experience do you want them to have? How old is your target audience? Exact age isn't important, but general stage of life ("middle school," "close to retirement age," "just started first job") matters. Many beginning writers pick overly obvious names, such as "Brick Stronghelm" for a tough character, or "Raven Nightfall" for a mysterious girl. This is as subtle as getting hit over the head with an anvil. Look for name meanings that are more subtle, and don't be afraid to be ordinary. After all, most people have ordinary names.   For example, the story "Silent Voice" features the main character "Claire Fields." The story is about a girl developing her voice, so "Claire" suggests clarity. "Fields" is a common last name that involves peaceful nature imagery. Use baby name websites for ideas. Make sure that the names seem reasonable for the ethnicity. For example, "Nazari" would be a good last name for a Middle Eastern character, whereas "Kimikho" would be a weird first name for a white girl who lives in Montana.
Develop their appearance. Figure out which phase of life they are in. Choose a name with subtle meaning, if any.