If you've ever written anything vaguely controversial, you're sure to notice that it isn't often easy. If, for instance, you're quite sure that the Bible calls adultery sin, writing that for others to read even if it's abundantly clear won't make you popular with the populace. Calling on thieves to repent won't make thieves like you. The fact is that writing from a biblical perspective by definition will cause friction. As John wrote, "Do not be surprised, brothers, that the world hates you" (1 John 3:13). Look, telling people, "You're wrong and need to change directions" is not going to come across positively even if you say it with all the love and good intentions that you can (had better) muster.
I've written stuff in the past that hasn't gone over well. I've written that husbands must love their wives. That usually flies okay because women really like that their husbands are commanded to love them and, frankly, there aren't a lot of husbands reading this stuff that simultaneously hate their wives. But write "Wives, submit to your husbands as to the Lord" (you know, word for word like it says in the Bible) and you will catch all sorts of flak. "Me? Submit to him? He doesn't know enough to come in out of the rain!" I'm shocked, of course. I was expecting a "Gee whiz, Stan, thanks so much for pointing out God's view on the topic. I can see that I need to change things and trust that God will do what is right when I obey Him." Doesn't happen.
So what can I offer for easy writing tips for Christians? Can I offer you any way to get along with people in your writing efforts? Absolutely! Follow this simple guideline: Write what they like to hear. Simple!
The easiest way to do that is to avoid all the controversial stuff. Just skip it. Don't even approach it. Does the Bible say, "God gave them up to dishonorable passions. For their women exchanged natural relations for those that are contrary to nature; and the men likewise gave up natural relations with women and were consumed with passion for one another, men committing shameless acts with men and receiving in themselves the due penalty for their error" (Rom 1:26-27)? Well, yeah, sure, but you don't have to point it out, do you? I mean, leave that stuff for those not concerned about getting along, who don't anticipate being liked, who don't care if people are offended by biblical truth. If you care about coming across as "nice", just don't do it.
Sometimes you'll want to approach controversial subjects. Take, for instance, the subject of marriage. Now that one is just fraught with danger. I mean, the Bible has all sorts of unpopular things to say about it. On the other hand, it has a lot of good things to say. And, after all, marriage is a good thing, right? So when you approach one of these minefields and you feel like you must go there, step carefully. Go with the "husbands love your wife" thing because you won't get much opposition there. Be sure not to go on to the whole self-sacrifice thing, like "as Christ loved the Church and gave Himself up for her" kind of stuff. But in today's climate, you can generally get away with bashing men for their failures as fathers and husbands and wives will eat it up and men will take it fairly well, so that's safe. On the other hand, don't push that whole "wives submit" or "let them keep silent and ask their husbands" kind of stuff. Sure, sure, it's in there, but there is hardly a woman on the planet today that wants to hear what God has to say about feminism and the like, so avoid that stuff like the plague. It's possible to approach controversial subjects if you do it carefully and selectively.
A word to be sure to keep out of your writing is "repent" or anything remotely connected to it. Don't ask people to repent. I mean, it is abundantly clear that the Bible is full of calls to repent and warnings against immorality and idolatry and all that, but they have Bibles, don't they? Let them read that stuff for themselves. After all, it's God's job to convict of sin, not yours. Telling people they're doing something wrong almost never goes over well. Pointing it out in Scripture and expressing deep and abiding personal concern and love doesn't make it go any better.
Bottom line, just follow this simple, biblical formula: "People will not endure sound teaching, but having itching ears they will accumulate for themselves teachers to suit their own passions" (2 Tim 4:3). Go with that and you will have people beating a path to your door. Oh, wait, is that a good thing? Hang on a minute ...