I think an important thing is for each individual player to flesh out their characters beyond their IC military service. Most players make some of their first characters with little-to-no backstory. Throw together some in-depth descriptions of your character's family (if applicable), maybe a sub-page within your character page for their family. Write two paragraphs on what basic training was like, referencing the
Training page and discussing which classes they excelled in or did poorly in.
Look at Characters like
Sune for example, where Brian had every aspect of that character fleshed out. Hell, Ramiro has
mortgage. These are all small ways to flesh out the setting for your character, creates interesting content and setting elements for GMs to use (a mysterious package has shown up at Ramiro's condo; Side Quest!), but it also expands on your character's psyche, personality, and interests. It helps to remind a player, when they're writing their posts, that this character will some day have a life outside of the military and that each character needs to have goals beyond military service, even if none of us will be around long enough to RP those goals to fruition because they are 10 or 20 year goals.
Maybe your character wants to be a Senator; they don't need to become a Senator while you're playing the character, but if it's a long-term aspiration it should affect how your character operates. When they're on leave they'll want to do certian things that other characters might not. Maybe it gives you an opportunity to write actual letters to your Senator, in-character, and post them to the forums. Does your character keep up on politics? Or maybe they're an engineer on a starship and want to retire from military service to open up a space-garage. If so, they should take an interest in learning about civilan personal crafts, maybe they spend their freetime on the ship browsing websites looking for that space version of a sports car they've always wanted, etc.
Also, If you keep accurate records of your finances, you should find yourself with a growing pool of cash. What does your character do with it? Do they invest it? Do they donate it? Are they looking to open up a small business, buy their own starship to strike out on their own, or simply put the money away into a pension so they can retire early? Speaking of retirement, what is your character's retirement plan? Do they have a favorite place they want to live? Maybe they met people in military service that they plan to settle down with? It happens in real life all the time that you go through hell with some people, and you all agree that you're going to get out together, pool your money, and buy a house on a beach, and be roommates forever. If your character doesn't have these future plans, maybe they're scared of the idea of leaving military service because it's the only thing that's ever given their life meaning or made them feel at home, and they can't imagine life without the military. These are relatively simply things to think about, but putting them in writing, even if not on the wiki but just in your mind or on a scrap of paper, it makes them real and changes the way that you will see and play your character.
A setting doesn't have to be the cool things that are in it. A setting can be expanded and made better simply by the characters in it, and the things that those characters own, believe, and do. And the best part is, that as long as what you're trying to do doesn't alter any character or location but your own and their home, you can do basically whatever. If you want your character to have a cool job smuggling cargo then buy a ship, throw it on the character's page, work out how much money your character would make, and work with another GM, FM, or Wes to throw some cool obstacles in your characters way that you may need some higher permission to use (police forces, military, gangs, etc.). The tools to creating a cool world with cool adventures are already available to every player without the need to take the time, effort, and energy to draw up lengthy wiki articles, as longs as it's something simple and doesn't mess with anyone else or the setting. I didn't get NTSE approval for Ramiro's condo and the loan, nor do I plan to get approval when Ramiro heads back off to military service to rent out his condo, nor do I believe that anything along those lines should require wiki articles and approval.
EDIT: The best part of promoting this approach is that it's something I think most players could get behind because it's completely self-serving. You're making a bunch of cool stuff for your character, that nobody else gets without going through the amount of work that you did, gives your more things to RP about which equals more fun, and makes your characters look so much more fleshed out and just all-around better.