Most people think that they are disorganized because they have alot of stuff. NOT TRUE!! Sometimes it comes from living in one place for a long time and not purging on a regular basis.
I come across these types of projects all the time. One day you just wake up and want to simplify! Don't worry, Erin is here for you.
Since there is years of build up, often items are placed where they fit and not where they belong. When you take on the project of simplifying your home, there will be alot of shuffling or relocating of items.
First of all, there probably won't be room to relocate everything to where it should go. Instead of leaving piles everywhere, set up a staging area. Choose an extra bedroom, corner of a living area or basement. Hang post its on the wall above your piles indicating where the items should go. Its better to have one room taken over temporarily by the excess then to have piles everywhere.
Tackle one project at a time. Finish one room or area then move to the next. Don't forget to bask in the glow of your newly organized home!!