I, for one, almost never include morals or distinct messages in my fiction. I’ve always been more about writing a story first and getting incidental messages across as they happen. That isn’t to say that I disagree with teaching morals in fiction, it can work really well, but you have to be clever about it.
1. Know what you’re doing
Really, this should be self-explanatory but often gets lost in translation or otherwise just gets lost. A moral only ever works if the audience actually knows what you’re trying to teach, a message being similar in that its intent has to be clear. Without pointers, messages can easily be muddled up. Take ‘war is a horrific abomination’ as your intended message. Glamourising the action and the battle sequence will not help you put that point across.
2. Be Subtle
Beating someone over the head with your cautionary tale is not going to make them remember it any better (often it’s quite the opposite). Neither will a last gasp statement that outlines your message. Show, don’t tell, being the golden rule of pretty much all of fiction, is a great thing to employ here. Show us why X makes Y happen or whatever. It’s much more believable that way and is more likely to stick.
3. Avoid Tired Cliches
It’s been done before and most likely by someone your audience, new or otherwise, has their own opinion of and that will taint your work. Nothing should really affect your fiction other than you.
Thanks for reading and enjoy your day.