Often, one of the hardest things to do in the character-creation process is to write a good background. It's a talent that not everyone possesses – just like creative writing, which is more or less what it is. But before anyone gets to depressed by the idea that they HAVE to be good at creative writing, that's just not the case. There are some tips and hints that can really help create a cohesive story that meets the goals of a background.
Step 1: Gather InformationJust like with writing a description, the first thing to do is gather some information. This time, we're going to start with making a list of things about your character's abilities. How strong, smart, fast, willful is the character? These are all things that will have roots in the character's history. Then look at skills – cooking is not very important to "justify", unless it's at a high level. But military or technical skills are. Not everyone knows how to shoot tank cannons or mortars. Very few people know how to blow stuff up safely. Many people can use a basic computer, but anything beyond that requires training. So, get all those listed out. It's pretty easy to do – just write down stuff that's in +stats.
Another set of information we need to talk about is people and places. Your character didn't "grow up" in a vacuum, after all. What were the names of the parents? What did they do for a living? Did she have any brothers or sisters? What were their names? Other relatives? Has this character had jobs in the past? Did she go to school? Where were the skills learned and when? This is the part that takes the most imagination. If you're having a hard time figuring it out, just take it one step at a time. Go down each item on your list (attributes and skills) and ask yourself, "why is she like this?" or "Why and where did she learn this?"
Then, once that's done, spend a little time sitting back and thinking about what the character's likes and dislikes are. If there are any strong ones (say, for example, that the character has a strong bias against people from the Mekong Dominion), ask yourself what caused this view. Also, think about whether or not everyone in her family is still alive, where are they, how good/bad is the relationship with each? And most importantly of all, why has this character come to Khayr ad-Din?
Step 2: OrganizingOnce you've done all that, you should have a big, long list of disjointed facts about your character. Take a moment to arrange these into something like a chronological order – obviously the character wouldn't learn to design mechanical hardware at age 3 and quite possibly wouldn't learn cooking while she's in the military.
For most everyone, there is a simple progression that starts with childhood, goes through primary school education. Then the person might go on to a secondary education and/or military service. Past that, perhaps some job-specific training. However, some people deviate from that. Some won't ever have a secondary education. Some have interrupted primary educations. But all the same, nearly everyone will learn college-type skills when they're adults, so just try to keep that in mind. Unless, of course, your character is a child prodigy. Then you'll need to think of the intense stress they will probably be under.
Step 3: The WritingNow it's time to put it all together into a story. For the most part, what you have now is a half-finished product. It is a list of things that the story needs to tell. The best advice I can give at this point is how to pace the story, as pacing is a very important part of storytelling.
The first trick is to cut out all the "absolutely nonessential" stuff. If a particular ability or skill really has nothing to do with why the character is who she is, drop it from the list. If she has two sisters and a brother and they all get along well, that's all you have to mention. Don't bother naming the family in the story unless there's some other reason for them to be there.
The second thing to do is to highlight the most important aspects. If the character is a professional chef, then cooking, business, etiquette and bureaucracy are probably going to have more of a role in the background than small arms, dodge, drive, and so on. That's not to say those shouldn't show up, but they're going to be minor parts of the story.
Now that you've given "weight" to the parts of your notes, start with writing the more important parts. Flesh those out with details in a story-like manner. Once the main portions are done, go through the rest and give it a much quicker take. This will make your draft.
The last step is to refine the draft, changing the wording to fit the pace you've set, making sure tense is the same all throughout the story, and making sure the perspective (first person or third person – I did vs. She did) remains constant through the story as well. And that's your finished product.
A Couple Other HintsThere will be parts of your story where nothing really takes place for a while. The "timeline" approach would start the next section with a date. Rather than doing that, think about a "gloss over" sentence or phrase. "Everything went smoothly for the next two cycles - Jauneth studied and partied like any other student. It wasn't until..."
"Don't show a gun in the first act if it won't be used in the third." This is an old playwrite's rule. Basically, if you make a point of putting something into the story, you're saying it's important and needs to be considered later. There's a certain economy to consider in stage performances. You can't have a prop just to have a prop. If someone's going to wave around a gun, there's a purpose that gun is there. The same can be said for backgrounds. Don't put it in if you don't intend to use it (or have the staff use it against you some day, possibly.)