Don't preach. Yet if you have no agenda, you have no story.

You can't hit readers over the head with your views; most of them won't stand for it. Yet you -- and by extension, your characters -- must care passionately about something or else the story won't matter to anyone. I guess this is a variant of the old adage, "Show, don't tell." Show the reader that your characters are passionate about something, rather than saying, "Meredith thought that music was more important than anything." -- Rachel Holmen