Many retail stores sell bins, cubbies, chests, shelves, baskets, and bookcases that are fun colors and kid-sized.  When you bring the stuff home, have your child help arrange them in the room.  Then they can help you decide which toys will go into which bin or shelf.  Finally, label the storage items with classifications, such as puzzles, action figures, ponies, etc. so that everyone remembers where everything goes.  This will also help if you hire maid housekeeping services or even a babysitter. They will have an idea of where to put things if they are tidying up the child's room.

Make cleanup time a part of the night routine.  Create a game out of it... "Let's see how many toys you can pick up in ten minutes!  Ready…set…go!"  At first, be involved in the cleaning process and try to make it a positive experience.  They will be learning healthy organizational methods that will last a lifetime.