A Christian...But not preachy story?

Speaking of Doug Tennapel (I know that's the wrong captilization, but I'm too lazy to bracket it so it's not a wiki word), The Neverhood is worth looking at (if you can find a copy, since it's rare, but I think there's a stripped-down version of the game available online with Doug's blessing) if you want to go the "allegorical" route. Although it's obvious that it's based on the Garden of Eden and the Biblical story of Genesis, it's mostly just a wacky little humorous adventure with good visuals and great music. It's based off a Bible story, but it merely uses it as a backdrop for something with universal appeal by not beating one over the head with its message and not trying to moralize. It's inspired by the Bible, but its whole purpose is not to be Biblical.

...Also, it's worth playing because it's a good game, the claymation is awesome, and the music is both catchy and hilarious.

Be careful to avoid the trap of making Christians perfect Mary Sues and non-believers bad. Make all your characters have good and bad points.

Make any religious practices natural to the story and characters and not shoehorned in for the purpose of an Aesop (LM Montgomery's "Anne of Green Gables" was very good about this. Going to church was a natural part of their slice of life—Anne even had some of her misadventures in church or Sunday school!)

Don't fall into the trap of writing "narrative narrative narrative (insert theology lesson here) narrative narrative..."

Read some literature written before about 1950. Writers back then seemed to be much more skilled at writing religion as an everyday part of life without making a big deal about it.

Good luck!

As a corollary to what everyone else has just said: Look for some of Graham Greene's books. Any decent bookstore should carry his work. You might also want to keep your eyes open for Shusaku Endo, although since his work was Japanese (obviously) it might be much more difficult to find. Both of them were Catholic Christians who dealt with moral and religious themes and allowed their faith to inform their work without getting preachy about it. The Christian characters have moral failings that they struggle with, and not all of them get happy endings, either.

Write characters who happen to hold Christian beliefs (Whether that be a literal belief in Christ or just having a moral code which is espoused by the man) don't focus on the fact that they are Christian, make that incidental.

If you're making a story about Christianity in some sense than that would defeat the purpose, but if you just want your character to be christian and the story and themes are something else entirely than that's probably the way to go.

You can make it have Christian themes without being explicitly Christian. Think of the principal values that Jesus espoused and make them prominent aspects of you character, show them in a positive light. Even if you are not promoting the religion, you are still promoting the values held by the religion.

melloncollie: I would say to focus on the parts of Christianity that you find most positive/inspirational and don't try to proselytize.

My thoughts exactly.

Also FallenLegend make sure your Christian character(s) are relatable as people. Plus have a few people read your story all the way through in one of your drafts to see if it is too preachy. Make sure that you have a variety of people read your story, not just Christians.

That said write what you want to write, and have fun!