Author and "Organizing Lady" Sandra Felton has written many books about organizing for "messies." She herself is a recovering messie so her advice comes from first hand experience.
Cleanies vs. Messies
She often writes that "cleanies" tidy up automatically, without having to be reminded or nagged at. That’s because they immediately see what is out of place and feel uncomfortable until it’s put away. Cleanies can find it hard to understand why messies don’t just spend a few minutes getting rid of the obvious mess in front of them.
But messies tend not to see the mess until it gets so big that they can’t find anything or put one more thing down. At that point, it seems too overwhelming to do anything about. What messies need is a way of reminding themselves to tidy up regularly, since visual cues don’t work for them.
Make a List
I suggest having a list of all the tidying tasks in the house posted prominently. Breaking the clean-up into smaller tasks means you can glance at the list, find a task and do it in a few minutes. It also means that other family members can do the same thing (yes, enlist all of them!). Note that this list is for straightening up, not for house cleaning, so it should be obvious whether a task such as "clear the kitchen counter" needs doing or not.
Pair Up Tasks
Another idea is to pair up tasks with other activities you do regularly. One of my clients decided that she wouldn’t check her email until she spent a few minutes clearing off her desk. She didn’t have to finish clearing it, just put in some time. But since she checks her email a lot, it will get tidied up pretty fast!
Write It Down!
The important thing to do is write down the tasks and make a habit of looking at the list. Don’t try to remember to do them. Don’t worry that you shouldn’t need to be told to clean up. It’s okay to need a reminder.
Do It Now
Don’t put them off for later. Tasks that take two minutes or less are worth getting out of the way right now, because a pile of two minute tasks quickly becomes half an hour or more. Put your purchases away as soon as you come home from the store, for example, even if it means walking all over the house.
Simple habits like these will make a huge difference in the clutter level of your home. Start right now!