Create routines! As behavioral scientists have proven, humans can learn by watching others. Routines give something tangible for other family members to follow. If for example, you do grocery shopping faithfully on a particular day of the week (with limited trips in between), family members are more likely to let you know what they need before you go to the store. By letting the natural consequence occur (of possibly having to do without a favorite food or item for the week), the routine becomes even more powerful.
Create areas for each family member to store personal items! This is very important. If you designate places for each person to keep items, they will be less likely to leave them just anywhere. If a particular family member is having trouble finding space for their items, help them problem solve. Providing a solution is a positive way to avoid conflict started simply by nagging. Less time having to organize means more time to do fun things so hopefully the behavior will be self-reinforcing. If not, issue small rewards from time to time such as taking the kids out for ice cream when they pick up after themselves.
Designate clutter-free and "clutter appropriate" zones. I will say that I am using the words "clutter appropriate" loosely. What you want to do is designate some places in the household were some clutter can be tolerated. A good example is a play room. I do encourage my clients to work with their children on creating routines for picking up toys regularly so things don't get out of hand. What you don't want is for so many toys to be out at once that you can't see the floor. The same principle would apply for a garage or basement.
Good organization doesn't have to be perfect! Having everything look perfect is not the goal. What you do want is for areas in your home to be functional. You also want to be able to find things easily and reduce your stress level. Remember that those famous organization gurus that are on TV and in magazines have access to a staff!
Unleash Your Organized Me!