The key for optimal kid-closet-organization, is to keep things within reaching distance for your kids. We are HUGE fans of these Command hooks, and they end up all over the place....right on the inside of the closet, low enough for kids to hang up belts, hats, jackets or backpacks.
Putting shelves in at kid-height also makes things easy for them to get to their toys or clothes. Plastic bins with easy to open drawers, keep things like underwear, socks, PJ's and pants. This also makes it easy for kids to put their own clothes away as well.
Because it would be a huge pain to move the clothes rod down a few feet for my 4 year old (and he'll grow so this would be a double pain to move it back up in a few years), we moved the step stool from the bathroom in his room so he can move it over to reach his shirts in the morning. Luckily it fits nicely under his chalkboard table for easy storage.
Again, Command hooks on the back of the doors also hide dress up capes, backpacks and other things that need to be kept off the floor.
We also store bedding for the kids in their rooms. This frees up storage in the linen closet and makes it easier to access for those middle of the night emergencies.
I hope these tips helped! If you have any of your own tips or tricks to add I'd LOVE to hear them! I'm always on a lookout for better ways to keep all of our crud together. Ha!