Empower them to create. Define limits to encourage problem solving, but allow individual ownership of ideas and work. Be especially sensitive to questions as they first start to work. If there are more than 1 or 2 questions, take more time to clarify for the whole class. If there are slow starters, make sure they understand, but allow time to think.
Many teachers use topic motivation related to student interests, experiences, and concerns.
Consider student development. Consider special motivational activities to enrich their frame of reference for creative media work projects. These might be sensory exercises to make them more aware of texture, tone, hue, depth, intensity or some other visual quality being learned. Children enjoy role playing, stories, poems, and so on. These activities can be used to foster richness of imagery in their work.