General Information
Name: Obviously, your character's name
Gender: Male or Female, obviously... I hope.
Age: How old is your character?
Current Residence: Where do they live/work now?
History: Tell me about your character from their life as a child all the way until present time, including all major events (both good and bad) to some degree to flesh out your character.

Appearance
Visual Appearance: Any possible image goes here.
Clothing and Armor: What does your character wear? Include everything they wear in detail to give us a greater image of what they look like.
Personality: What kind of person is your character? Describe what their persona is and how they are, how they act, what sort of things they like/don't like, their flaws, their strengths, and so on.

Visual Age: How old do they LOOK? You may have listed your actual age in human years, but Shinigami that are like, 200 years old often look like they're in their 20s in human years.
Division: What Gotei 13 Division are you with, if any?
Divisions: Have you ever been with a different Division?
Rank: What rank are you within your Division?

Zanpakutou
Zanpakutou Name: The name of your Zanpakutou
Spirit Appearance: What is the true appearance of your Zanpakutou? What does the actual spirit look like. All Zanpakutou are living beings, so they must have a true entity.
Inner World: Simply put what does your inner world look like, that little dimension were the spirit of the zanpakutou resides.
Sealed Form: What does your Zanpakutou look like in its normal form, the way your carry it around?

Shikai
Shikai Release Phrase: What's the phrase or word you use to call out your Shikai?
Shikai Appearance: What does your Zanpakutou look like after you have released it?
Shikai Abilities: What does your Shikai do? Describe the ability of your Shikai in detail and what strengths and weaknesses are gained upon using it. (No more than 3 abilities)

Bankai -Keep in mind, not everyone can have bankai, let's not be over the top. It tends to only be if you're Captain-level, and sometimes in Lieutenant-level.
Bankai Name: What is the name of your bankai?
Bankai Appearance: What does your Zanpakutou look like after you have released it?
Bankai Abilities: What does your Bankai do? Describe the ability of your Bankai in detail and what strengths and weaknesses are gained upon using it. (1 to 3 abilities allowed, depending on the strength of your character and their stage of mastering their Bankai.)

Learned Kidou:
List for me what Kidou your character is proficient with. Custom Kidou are allowed. (No more than 6 Kidou are allowed per character) A list of canon Kidou in Bleach is here:
http://en.wikipedia.org/wiki/Kidou#Known_kid.C5.8D_spells