Credit for this goes to Leopardspots on Warriorclan.
Just some helpful things for creating a character you really want to stick with.
Name: Make it meaningful. Making a cat named Brownpelt because he's brown makes your cat considerably less interesting than, say, a cat named Oakstrike because he is mighty and powerful.
Appearance: Try to envision the cat as you write it out, and be descriptive. Don't just say "he's big and brown with blue eyes". What shade of blue? What shade of brown? What markings on his pelt? Big as in huge and muscular or long legged and tall?
Personality: Try to have at least two positive, two negative, and two neutral aspects of their personality. The neutral would just be like, introverted vs extroverted, types of intelligence(observant, philosophical, creative), level of courage, etc. Positive would be whatever they value about themselves(wit, loyalty, etc), negatives would be what they don't think about themselves(arrogance, insecurity, etc). This is what balances a character, no one is pure good or pure evil. For other things, you could add their favorite season or food or something.
Skills: These are mostly their abilities (loyalty is not a skill) like their ability to hunt, fight, swim, climb, remember things, etc
History: Their story from before you started roleplaying. This fills in their background, alters their name and personality (maybe even skills and appearance!) and tells behind their motives. It most of all needs to add up and make sense to be good. If their parents or best friends died they would not be a cheerful cat, please stop adding in horrifying backstories and writing your cats as happy it doesn't make any sense. Also, keep in mind other events in the Clan's history if you know them for help creating their background. If there happened to be a (for example) tsunami when your cat was a kitten, use that! It ties your cat in to the storyline!
Family: If your cat does not have family, just make up some random names and list them as parents or siblings. Never use someone else's cats as family without permission from them.
To post an audition, make a new topic in the Auditions page. Post your audition and wait for a moderator or advertiser to look it over. You will have to fix it at times, but it is okay. If you give up, it doesn't pay off.