Teaching organizational concepts needn't be a difficult or separate activity. Toys lend themselves to organization. While discussing toys' colors and shapes, separate them out in different ways. Train tracks, straight and curved. Books, hard and soft back. Dolls, plastic and cloth. Look at types of toys--rattles differ from stacking blocks and plastic beads differ from beach toys.
Include children in chores--folding socks, t-shirts, pants, etc. Sizes? Long sleeve short sleeve? Colors? Season appropriateness? While cleaning out a closet, explain the reasoning "behind your madness." Why are some items garbage while others get donated? Your child will experience the process and not just see a clean closet. He will understand the effort.
Continue to apply organization as interests change. Older children interested in construction work may help sort through nails and screws. Teach the difference between flat and Phillip's head. Look at lengths and widths. If you have a budding chef, work on organizing spices, extracts, marinades and flavorings. Whatever your child enjoys, he can organize it by choosing what detail to focus on.
An important teaching point is for children to evaluate and make judgments using their maturing reasoning skills. What aspects make Elmo a stuffed toy? Is he a person? Would you classify him as a cartoon character? Toddlers take these questions seriously, and see them as fun. Eventually, your child will take over and look for nuances in sorting.
Once, my son separated his birthday gifts by friends, uncles, aunts and so on. That might seem silly to us (that's not the way I would have organized his toys), but keep in mind that truly organized people have a formula that works for them. Children need a model to start, but they eventually will make their own patterns.
Preschool and early elementary teachers should implement a routine and system for activities and schoolwork. Not only should parents continue with the teacher's organizational models, but they should also explain the benefits. "Is your homework in your take-home folder? It is nice to know where your homework is."
Aside from neat school desks, sans under-the-bed-clutter and labeled desk drawers, organization leads to confidence. Organizing thoughts and ideas, spoken or written, will always benefit your child. Look at how so many students struggle to write a school paper; they often "don't know how to make it flow." What this so often means is that their ideas, while strong, are unorganized. The ACT's writing portion is in part scored on the writer's ability to organize.
Organization can't be taught once or the night before a big test. Modeling organization is the best teaching method. Look at other life skills that you already teach your child. You probably have room to add organization to the list. Your child, and his future teachers and bosses, will be glad you did.