Two words for you: blackout curtains.
Sure, you (or your significant other) wants cute curtains for your kid’s room. But humans are supposed to sleep in the dark. Kids are not an exception to this rule. Your child will sleep better – at night and during naps – if you add blackout curtains to whatever window-dressing setup you currently have in place.
Find them at most home products retailers like Target, or for those of you in the cute curtains category, Pottery Barn.