There are a few guidelines as to what you should or shouldn't include. One of these is what Blake Snyder calls "the promise of the premise." What do people expect from your story as they read it? The fun and games should fit in with the genre you've chosen while still being fresh and unique. Don't necessarily go with what people expect, but do go with what they want. For instance, in a spy thriller, most readers want and expect a lot of cool spy gear, so you might want to work some in. Then, to keep things from being boring, put a fresh spin on the idea.
Everything in your story needs to have a purpose, whether it's to highlight character or ramp up the tension. As much as you may want to throw a model car hobby into your book, you should only do so if you can make it important. Call backs are great ways to weave the fun and games into the story--making the villain slip on a model car right as he's lunging at the hero in their final duel, thus granting victory to the hero would be a viable way to make that model car hobby pull its weight in your story. (I'll discuss call backs further in a future post.)
And lastly (and this goes along with the above point), don't let the fun and games hog the show, thereby bogging down the plot. If your hilarious chase scene is too long and convoluted, you'll lose your readers after the first few laughs (been there, done that). Keep things moving.
Have you put any "fun and games" in your story lately? Know more tips for how to incorporate these fun elements? Feel free to share. I'd love to discuss this some more.
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