An author friend and I compare our writing to cooking up a dish. After writing the first draft, she likes to let it "simmer" while I prefer to call the process "marinating." Just as in cooking a recipe, authors must choose the ingredients to use and in what proportion, how long the dish needs to cook, etc.
I dare to take the comparison even further and add that, like a chef, one must choose how spicy to make the dish and which spices are necessary to achieve the desired effect. The ingredients and spices used might include dragons, hunky he-men, glamorous heroines, dastardly villains, cute kids, blood-thirsty vampires, sword fights, dorky geniuses, superheroes, ghosts, wizards, elves, spaceships, and light-sabers. Take your pick.
Mix well whatever ingredients you've chosen, being sure to use proper grammar, spelling, and punctuation. Pack into clear sentences that aren't overly complicated. Form into neat paragraphs. Divide into chapters. Let the first draft ( or even the second or third! ) marinate until well-seasoned and satisfactory. Edit when done, then serve up to book-hungry readers!
Keep on cooking until you get the results you desire!