Oh, I LOVE decluttering!!! My mom is a keeper of all things, just hates to throw things out, but I LOVE organization and pitching things! Makes me feel real good to look at something and toss it in the trash. Or in the Hannah Home pile if it’s something the shelter can use.
My suggestion - take one room at a time. I usually start with one place, take everything out of that place (for example our master bedroom closet) then go through it. Keep or pitch? Do we actually use this? I make a trash pile, a give-away pile and a keep pile and then put all the keepers back nicely, then take care of the give-aways and trash. Then I move on, either that day or another day. Right now we’re clearing out a back guest room which has become our attic space. We do an hour a night. Go at it slowly or you’ll go nuts! Just take your time and before you know it, you’ll have a lot less stuff to deal with.
Then the key to keeping things organized of course, is putting things where they go from the get-go. An extreme example - My mom thinks I’m nuts, but really, if I hate something the moment I get it, then I’m not gonna keep it and let it clutter up my life until it’s “cleaning day”. Christmas cards that are only signed with no personal note and I know I’ll just stash in some cubbyhole go right into the trash, unless the card giver actually took time to WRITE to us - therefore Grandma’s and Grandpa’s are about the only cards we save. Wedding presents that were just AWFUL went either right to the trash or the give-away pile. The same with baby gifts. Christmas gifts - the same. My in-laws always give us a recording of their Protestant church’s Christmas songs and we don’t like the songs (most are secular), so the package gets opened and then goes right into the trash. Aren’t I TERRIBLE???

My MIL gave me an awful birthday gift - trash. My hubby got some really weird socks that he can’t wear with anything - give-away. Anyway, you get the point. the nice thing is that our methods must clearly be working because lots of people comment on how clean and uncluttered our house is. Everything has its place.
Now if I can just get my husband to throw out that stupid plastic 5" alligator he acquired in college that he thinks is just too awesome and I think is just plain taking up space!

It has a mouth that opens and closes, that’s the only reason he likes it. It’s place is in our master bedroom closet, husband’s side, top shelf. Always there, looking at me.