Marianne dubouloz

That's a nice widget.
I like that widget.
Something you plan to release on the marketplace?

I have rules, but I'm not heavy-handed with them. It's pretty much anything goes, with a caveat: if you post something that could generally be considered too intense for all audiences (like with swear words and all), then use a content warning in the title. An [R} (like for an R rated movie) is all that I require, but I find that many members will add more like "language" or "religious" in the title line. There have also been members who haven't used the R, and I've had to put it in myself. I'll usually reply to their topics and include that I added the required content warning to the title line. Hopefully they learn from it. Also, in the rules, I specify a few things which are not allowed like porn, political endorsements, advertisements (unless approved by me), and since it is an artistic community, I state clearly that I, in my sole discretion, am the one who determines what constitutes porn, political endorsements, etc. In the words of "W," "I'm the decider!" 
I generally try to lead by example. My members will often post poems about subjects they feel strongly about, and I always let it ride even when I don't agree. I'll post a reply that addresses the qualities of the poem itself, not so much the content. I did have a member who recently posted a long anti-gun rant (er, poem). I had to clean it up, because he just copied/pasted from another site where he had posted it, and it was riddled with garbage links like [edit], [follow], [472 followers], [830 following], etc. I had to waste my time cleaning that up, so I was already in a bad mood. I happen to like guns, so I used the topic as an excuse to post some opinions of my own under the guise of inciting that member to post more poems.  A few days later I posted a provocative piece of my own. 😉 But generally, I have a good group and haven't detected any outright hostility.

This is probably the most important area for a large board.... and I always keep this "You can't please everyone" in mind...
I agree that if you want to deal it in a right way, make sure that you have a clear and simple guidelines...
and never forget this
Be fair,
Stay away from double standards,
Judge your members according to rules (guidelines), not your personal view/opinions (You should/must also follow/watch your moderators very closely to ensure that their personal opinions are not involved in decision-making.)

It's what IPS recommended years ago, and it is a great approach. 👍🏻