The last blog I explained that you should have the basics of the character down (male/female, place in story, what personality fits that place as in smart/flighty, strong/weak, loud/quiet, even tempered/not so much, impulsive/thoughtful, emotional/closed, you may even have the physical description such as hair color and facial features or skin type) before you try to expand on the character. Once you have the basics down, you can decide on the other things. At this point a good place to start would be on age and ethnicity. Is she a twenty-four year old Cuban-American or is he a fifty year old Chinese man? The physical characteristics may sprout from the racial background or the other way around. Also, the personality may decide the race. If you want a loud, passionate lady, you may want her to be Puerto Rican or of African descent. If you want a quiet, obedient wife, you may want an Asian. Now, those are stereotypes and no character is supposed to be a stereotype in a story, especially a main character. Still, remember that their genetic race often influences how they were raised unless they were adopted.
Another thing is that what they remember can influence who they become or what they talk about. Some of my friends that are five to ten years older than me enjoy reminiscing about cartoons and fads I don’t remember while I enjoyed fads they considered to “juvenile” for them at the time. Knowing their birth date and where they were raised can be helpful in knowing some of their memories or conversations later on. Knowing that can also tell the author what may have happened in the character’s life such as I remember what was happening when the World Trade Towers fell, even though I was just a kid at the time but don’t remember what I was doing when I learned of foreign terrorist attacks in my youth. Maybe your character was working at the Mall of America that day when it was shut down or was injured in the attack on the Pentagon. Things like that need to match with age (why would a six year old be at the Pentagon?)
Once you have age and ethnicity set up you can decide things like how strict or relaxed were their parents? How outrageous were his or her friends? In Pennsylvania the character may have been raised with Amish friends while in Texas they may have had mostly South American schoolmates. All this can be included in basic background of the character and may take you only a minute or two to decide on. The rest should take a little longer as we go more in-depth.