This seems easy for some people and families, and a perpetual problem for others. There’s probably a large book to be written on the reasons and psychology behind this. But if clutter is an issue there are ways to massively improve the situation you are in.
Set some time aside to plan a compete change in the house. Think of ways to have rooms set our efficiently. Think of hotels and libraries, only you will live there.
Find the things that do need to be disposed of, and simply get rid of them. Old bathroom products, cosmetic and similar item in the kitchen need to go. 2 years is about the limit for anything of this nature. Then find any items that have been doubled up on- keep you good blender and coffee machine, and give the old ones away.
Find items that need to kept, but not out in the open. You can either box then for the attic of find space in the back of kitchen cupboards. If you have suitcases for annual travel you can use these for storage space.
Keep floors as clear as possible, and use storage space above your head. Bookshelves at head height don’t feel as intrusive as storages space at your feet, especially if they are half filled or contain a lot of decorations. If bookshelves do house a lot of books you may find you can store a second layer of books behind the first. Keep the front layer for neat books and matching box sets.
Use storage space under your tables, television, furniture …etc. Keep to surfaces clear or very sparse.
Light coloured furniture and walls help a feel more open, as do windows and natural light. Redecoration can make a room feel very different. What we see as untidy and dirty is occasionally just a drab look.
Do one room at a time; a bedroom is often a good starting point. Set aside a day and redo the whole room. Good results in one room can inspire you get the whole house up to the same standard.