Set the Tone
Your kids need a dedicated area of the home to study, a place that clearly conveys, "It's time to study" as soon as they enter it. Let's face it, the kitchen table is not the best place for doing their math and their bed certainly isn't their best bet for reading assignments.
While dedicating an entire room to a study area is best, it's not always feasible. Choose a quiet room in the house, and create your child's study area in one corner of it.