I read an excerpt from Sandra Felton's recent book, Organizing for Life, on Amazon today (and I put it at the top of my Amazon list in the left column). I have quite a few of her books and I like all of them. As a reformed "messie," she brings insight and compassion into the problems disorganized people face.
Felton's theory is that messy people treat themselves poorly by not being organized. They say they don't want to spend the time and energy to put things in order, but they then relegate themselves to lives full of chaos. She writes: "They are happy to show you how they do without the things other people who recognize their worth and dignity provide for themselves."
Being organized, then, isn't about doing things "right" or living the way others expect you to. It's about respecting yourself enough to create and maintain an attractive and supportive home and life. It's something you do because you are worth it.
I recommend Sandra Felton's books. She has lots of original, clever decluttering tricks, such as the Mount Vernon method for tidying up a room.