Most cleaning advice goes something like "toss out five thing every day for 30 days" or "spend fifteen minutes tidying up every day" it's all about cleaning & organizing in small, consistent, continual burst forever and always (at least that's what it feels like).
But the KonMari Method is completely the opposite - in one fell swoop get rid of everything that doesn't "spark joy" and then organize what you're left with. It turns out that most of our possessions often don't "spark joy" and can be gotten rid of - which makes organizing much easier.
Of course, you have to get through the process of going through each and every possession individually first.
If you're anything like me (or most of us) you have a lot of "stuff" most of which doesn't spark joy - in my closet I only have one or two pieces that really, truly sparked joy. You'll also probably have categories of stuff that are much more daunting to get through - for me that was art supplies.
Going through everything you own, just to get rid of much of it can be quite a daunting task. What helped me was repeating "Jane, remember, you only have to do this once."