even 10 minutes or even better would be 20 or 30 minutes of lying motionless with eyes closed and allowing the mind to drift, wherever it happens to go, but focusing on relaxing by doing long exhale breathing, perhaps doing a body scan or focusing your attention on particular body parts but not keeping it focused on any one particular body part for that long, that general practice of deep relaxation while awake and being relatively motionless really favors the brain states associated with divergent thinking.