A box for each kid K-12 ... I had a professional organizer at my house (what a treat!) and she suggested this system for pictures and papers, etc. 1st year, 1-2, 2-3, 3-4, pre-K, K, 1st grade - 12th. So simple, but so brillant.
Bored Jar. Fill with things to do (clean your room... or go get ice cream). When your child complains of boredom, tell them to pull an idea from the jar and they have to do it, no questions asked! Love this!