Before you can organize a messy house, you first need to get rid of many of the things that are making it messy. This can take a while, so do not expect your house to be organized in one day. Organizing a messy house may take some work, but it will be worth it once your house is neat.
Make three piles in your house: one for things to keep, one for things to throw away and another for things to give away or donate.
Go through each room of the house, including the garage, and put everything you find into one of the three piles. If the items you are keeping are already in their rightful place, leave them there.
Take the items in the throw-away pile to the trash and the items in the donate pile to a charity such as Goodwill as soon as you finish going through the house. This is important so that these items do not find their way back into your house again.
Get appropriate storage for your house so you can put away the items you are keeping. Outfit closets with shelving and buy containers with lids for children's toys. Footrests with storage space look great and are functional for a family room.
Create spaces for stuff. You and your family will still be living in the house, and houses get messy. If your kids always come in and dump their backpacks, put a bench with cubbies in it right inside the door. If you bring the mail in and put it on the kitchen counter, place a small basket there to collect it, so it does not slide around and get lost.
Put up shelving units. This will give you more living space in your home, as well as more storage space.
Rethink what you bring home. Houses tend to get disorganized when new items come in. There is not a place for them, so a place is made that is convenient but is usually in the way. If you do not bring that item in the house to begin with, you are saved from that problem.
Go through the house and declutter at least once a week. Throw out anything that is not needed and put away anything that is out of place. If you do it often enough, the house will not get too disorganized before it is time to do it again. Another method is to pick a different room each day and clean it. In this way, you do not have one big cleaning once a week, you just slowly pick up throughout the week.