Wow, that title could mean anything from my site going to a different place to my house to my spirit being lifted up. Well, I mean my house. If you're ever really serious about cleaning, pack everything into boxes and move it out of a room. I doubt you'll like what you find or how many boxes it takes to make everything work.
Okay, this is where I relate my major life change of address to my major passion: Writing.
So, in the same way the process of packing boxes, cleaning, and purging things gets rid of excess and just plain garbage, so too does the editing process clean up your writing. Just like taking all the shoes and putting them in the box of shoes while making sure the cat isn't in there. It helps to sort out any single shoe with no partner or worn out pairs or outgrown ones that no longer fit. In book terms, these edits clean out the orphaned plot lines that never developed, the character who doesn't actually do anything, and makes sure the book makes sense.
One thing to remember is that first drafts, like moving, are supposed to suck, but a box can't be unpacked until it's packed and a page can't be edited until it's written. Don't worry about decluttering it until you finish writing it. The boxes all get unpacked at some point.