It doesn't have to be elaborate, but separating mail into personal and bills and throwing away junk mail immediately will cut down on the tendency to stack piles of papers together even if you have no intention of keeping them. Keeping a space for homework, school papers, and family documents will help, as well.
Step #2: Create a System
Once you're in the habit of sorting things as soon as they come in the door, create a system for dealing with them. A filing system or binder system are both great choices, just make sure whatever you choose works for you.
You might split the categories into things like “finances” and “school” or you might create a series of categories more specific to your family and needs. Whichever you choose, though; make it both neat and easily accessible to encourage you to use it!
Step #3: Clear the Cache
Every week, your entryway sorter will fill up with papers (still much better than having them in piles around the house!). Once or twice a week, take the papers and file them into your system.
If there's anything you've kept that you determine you don't need, throw it away, and put the most urgent things next to the phone or on your desk to be handled in the week to come.
Creating a system will help you cut down on your paper clutter and make cleaning much easier!