There isn’t a single, perfect, moderation strategy. It depends who your audience is and what environment you’re trying to provide for them.
The temptation is to be general. Don’t swear or cause trouble. Try not to offend others. That’s fine, but boring.
I have a recommendation. Have at least one hyper-moderated area. This is where your moderation rules are insanely tough and only the best contributions make the grade. In this area you savagely remove discussions that are boring, don’t add value, talk about trivial things, lack enthusiasm or passion, too self-involved.
The challenge of getting something through the moderation phase might be exciting to some and provide interesting content to others.
Or try one area of the community with an extreme moderation rule. Perhaps you can’t use the word ‘I’ or have to support every statement with evidence? Perhaps you must be 100% specific. Perhaps you must add some unique perspective/viewpoint rather than repeating what others have said.
Turn moderation from an irritating task into a centrepiece of your community’s engagement efforts.