At least first and last. If your character has an alias, you may want to include that as well.

This could be anything, really. Most authors stick to male and female, but gender is a heck-of-a-lot more complicated than that. Consider how your character would identify themselves and explain.

The importance of sexual orientation changes depending on the story you wish to tell. For instance, a character’s sexual orientation may be extremely important in a Romance novel, but less so in an Action/Adventure story where no love interest is ever introduced. Regardless, consider you character's sexual orientation and how that might play a factor in their life.

While age can be as simple as a "number," it can also represent a lot more... For instance, age could also be an indication of mental / emotional maturity. Age can also be a mystery, for example a character who doesn't know their exact age because of a difficult childhood. Age may also be something your character fights against, for instance a younger professional always trying to "overcome" their youth or an older person always trying to be perceived as younger. Think about how your character relates to their age.

A character’s class or status will determine a lot of things about him or her, especially the way he or she feels about money and his or her customs, traditions, privilege, and treatment of other socioeconomic classes. Consider Will Hunting in Good Will Hunting and the damaging relationship he had with wealth / status throughout the film.

There are obvious things to list such as skin, hair, and eye color. However, don't forget to mention scars or tattoos, piercings, clothing choice, height, weight, and overall physical attractiveness. You should also consider how a character moves through space. Do they have a limp or a unique way they carry themselves. Consider how a confident person moves through a room verse someone with low self-esteem and account for these things.

Does your character have a personal item that is always with them? Does your character have a nervous tick or else collect model trains? Include habits, phobias, hobbies, diseases, and addictions. Quirks make characters more rounded and are outward displays of their personality.

In short, how does your character navigate the world of "right" vs "wrong" behavior? And, at the end of the day, who do they answer to? Themselves? No one? A higher power? If your character committed a crime, how would this act affect them (if at all)?

What are your character's strengths and/or virtues? What are they good at? Consider more than just physical strengths like "they can run really fast" and go deeper... For instance, are they good at empathizing with others?

What are your character's weaknesses and/or vices? What do they struggle with? Consider more than just physical weaknesses and focus on deeper things... For example, perhaps your character has a difficult time listening to other people and zero patience.

Basically, what is your character good at? Do they have any learned or inherent skills (like carpentry, firewood gathering, or magical ability) that separate them from the crowd? Even if many characters in your story have similar skills, make sure to describe how this character’s skillset differs from everyone else’s.

Education does not necessarily mean intelligence (intellect is a strength), but the kind of education, where the character got it, and why is often important to the story. For example, language plays an important role in a story with dialogue, as the character must speak and be understood.

What does your character like? What brings them joy?

What does your character dislike? What brings them despair?

Where is your character from? What language do / did they speak? What sort of parents do / did they have? What was their childhood like? Anything that got your character from birth to the beginning of the story is backstory, and you can toss in some family or cultural history as well.

What does your character do to earn a living? If they don't work, address this. A character’s profession often takes up a large portion of their life, so it’s important that the reader knows what they do and how seriously they take it.

Relationships are complicated. Talk about your character’s relationship to anyone they come into contact with regularly and who has a large impact on their life at the beginning of the story. Ideally, you should mention someone your character gets along with and someone they definitely do not get along with. Also, it’s a good idea to mention any romantic interests they have at the beginning of the story, their relationship with immediate family, and how they feel about being alone and in crowds of strangers (this ties in with strengths and weaknesses)

Whether or not a character’s religious beliefs play a huge part in the story, it’s often good to know what they feel about God(s) in their world. We’d also categorize superstitions under religious beliefs, even though these are usually defined as quirks (see above). Religious and/or spiritual beliefs (or the absence of) can really play a large part in how a character views the world and the people in it. Be sure to think these things through.

This item is last, but it should really be first. More important even than a name, a character’s goals drive the plot. What gets your character out of bed (if they have a bed) in the morning? What are they pursuing in life? Does this goal benefit them personally or does it benefit someone / something else? Is this goal selfless or selfish? Is your character aware of this goal or does it live in the shadows? A well established goal is VERY important for a compelling character / story.