When most people think "mindfulness," they think of some sort of spiritual self-actualization, like in Buddhism. This is accurate, but not the whole story. To me, mindfulness is a hyper self-awareness. It's not ignoring pain, for instance, but acknowledging it, making the necessary adjustments, and moving on. (Disclaimer: this does not mean the pain goes away like some will lead you to believe. Sometimes the acknowledgment is knowing when you need help, like medicine or a doctor.) In the context of home organization, it's knowing your habits and the way you think and act with the objects around you.
For instance, many of us have homes with a coat closet by the front door, but use an alternative door on the day-to-day, like a garage or side door. You may think the coat closet is the ideal place for, well, coats. And shoes, scarves, purse, whatever we need and use when we leave our homes. But what ends up happening? Shoes piled by the door, coats thrown over chairs, and mail scattered across kitchen counters. This is an incredibly common problem. Some of us may be able to train ourselves to walk across the house and use the closet as intended, but most do not. Or we do, but our partner, kids, or housemates don't.
Mindfulness, to me, means being brutally honest with yourself. I'm never going to tromp across the house and put things away the way some builder 60 years ago thought I should. Even if I had a coat closet by the door I use most often, I probably wouldn't use it. Out of sight is literally out of mind for me (great when it comes to hiding treats from myself. Inconvenient for literally everything else.) So I have hooks by the back door for coats, bags, and keys, a bench for shoes, and a shelving unit with slots for every family member to put their hats and scarves with space on top for sunglasses, mail, and receipts.
I'll be honest, it's not the most aesthetically pleasing arrangement, especially during busy weeks. I do occasionally have to go in and straighten things up. But I, and more importantly, my family knows where everything goes. And it's rare when things don't end up there naturally.