Beyond the general things listed on the regular RPA FAQ, there are special things a Feature Character app needs to have addressed.
1) What FEATURE are you applying for?
Occasionally, applications will be opened for several feature characters at once. Be SURE you note both in the SUBJECT and at the top of the BODY of your email, just which character you're applying for so that the RPA knows without having to dig too far into the application to find out.
2) What is the character's general BACKGROUND?
Between the movies and the books, there's quite a bit of information out there about the main Feature Characters. A general synopsis of what you know about the character, including major points of past development leading to this point, should be discussed. It doesn't have to be too detailed.. though it should highlight the things you feel are most important about the character's life, and that have shaped them into who they are today.
3) What is the character's PERSONALITY like?
Where the background was an account of physical events, there should be a section in the application on the character's personality. What is this character like? What goes on inside their head? What are their motivations? What are they good at, or bad at, that helps define them as an individual? Do they have quirks? Prejudices? Special talents? What do they think about certain key aspects of the world that surrounds them, such as the relationships with their friends, family, loved ones? Do they have a favorite ship, a favorite droid, a favorite planet? What do they think about their job? All of these things should be fleshed out here, to show your insight into the character.
4) What's the FUTURE look like for your character?
Where do you see your character naturally progressing over time, given his or her background, his or her current IC situation, and his or her galactic alignment? Give the RPA some idea as to where you're interested in taking things once you get the FC. :) Would your character retain their current job and position, or would they leave it in order to fully pursue some other aspect of their lives? What are some of your short and long term goals for personal development?
5) Why YOU?
Take for granted that there will be at least 7 or 8 applications for any open FC, if not more. Why should the RPA choose YOU over the other applicants? How is giving YOU this FC better for the MUSH than giving it to someone else? Explain how you would use the FC to create roleplay for other people and how your personal take on the character concept will make the MUSH a more interesting and better place.
This is important not only for the success of your application, but for your success in the character should your application gain you the spot- the RPA expect the player of a Force User to have the mindset 'where can I go to generate roleplay for others' and not, 'where can I go, to get RP for -me-'. A person who is selected who doesn't go out and use their character proactively to generate roleplay for others may eventually be asked to step down.
6) What's your ACTIVITY like?
Feature Characters are given to people who are active and consistently have access to the MUSH. People are expected to log in often during hours when players are connected to the game, and they should be willing and able to venture forth and roleplay with as many people as possible, using their characters to generate plots and as a tool for RP.
List in your application how often you log in a week (how many hours a day, how many days a week, the general time periods (like 8am-noon PST, or 6pm-midnight EST)) so that the RPA can know when you'd usually be online, how often you'd be able to roleplay the character, and when they might be able to roleplay test you should you make it to the second round.
7) Who ARE you, anyway?
Beyond activity, the RPA might need to know a little more about who you are and what you've accomplished, to get a good idea of your experience. How long have you been MUSHing in general? Where have you played before? Ever held positions like a Force User or a Feature Character that required an application/testing process for a special character which was used as a tool for RP? Ever been awarded for your roleplay achievements? How long have you played -this- MUSH, and what have you accomplished here in that time? It might also be a good idea to include somewhere what your IC and OOC thoughts on important issues are, like the Force (if applicable), combat, player killing, consentual roleplay, things of that nature. If you have roleplay logs on the internet that demonstrate your skills, list the URL, but be sure to point out any one or two you think are especially worth reading. Don't send logs in as attachments, please.
8) Anything you SHOULDN'T do?
Don't bash on people. If you want to say you'd be active, tell the RPA the times you usually connect and how often you could play. Don't say something like, "I'd be more active than who you've got now, they suck." or anything else that might betray you're going into this with a negative attitude, that wouldn't be able to work with your peers once hired, or that you can't conduct yourself on a professional level.
Don't turn in the same application over and over, if you can help it. If your last Ackbar app didn't net you the FC, and the character opens again, you aren't doing yourself any favors submitting the exact same thing a second time. Look over what you sent in before, and see if it couldn't benefit from a reorganization or reformatting. Rework it enough to where it's up to date, maybe even put a new spin on it, if you think that'd help. Remember, you want the RPA to know you're creative and full of fresh ideas, and this is a great place to start.
Don't apply for more than one FC at a time. Pick the one you're the most interested in, and devote all of your attention to applying for that one. :) Otherwise you'll appear indecisive and as if you really aren't devoted to the concept of playing any of them.
See also: Force App FAQ and General RPA App FAQ