I'm leaving it quite vague because it's an open setting and I don't want to constrain people's imagination. I'm going to set it a few hundred years after Tarmon Gai'don though, so we shouldn't have any remaining living characters from the time. Otherwise, just try to give your character a reason to be out in the world, so it's easy to set everyone up together. You can also set yourself up with another player to have a linked background, as family, friends, warderbonded, colleagues, rivals, enemies, etc.
Probably something like this:
Name
Character description (how she acts, reacts, what she likes and hates, what she fears and scorns, sentimental attachments, nervous tics, etc.)
Physical description (What she looks like)
Background (How she got where she is)
Allegeances, friends, rivals and enemies
Special abilities (Can channel the One Power, wolfbrother, blademaster, never forgets a taste, owns lands and commands the loyalty of people who live there, heavy sleeper, etc.)
Strengths (Climbing, sewing, history, etiquette, swordsmanship, intelligence, firearms, poisons, heraldry, endurance, strategy, stones (the game), diplomacy, hearing, etc.)
Weaknesses (As above, other examples could be Strength in the Power, One Power (fire), visual acuity, singing, dancing, agility, swimming, memorisation, herblore, engineering, riding, reading, etc.)
Obviously, I'll probably want to tinker with a few things, and may, during the course of the game, ask you to add some things to one list of the other. For example, if you put visual acuity as a weakness and decide to use a bow at some point, even though archery was on neither list, I may ask to have it added to weaknesses.
~Master Splinter
Victorious in Bergioyn's legendary 'Reverse Mafia'. *MySmiley*