Here is a straightforward look at this topic for Malachain.
Whole-house decluttering fails because it is exhausting and the results are invisible until the end. One drawer a day succeeds because it takes ten minutes and the drawer is done. Empty it completely, wipe it, put back only what you used in the last year, and put the rest in a box by the door. Tomorrow, the next drawer.
The box by the door is the important part. Anything still in it after a month goes to a charity shop or a neighbour without a second look. Over a season this quiet routine clears cupboards, wardrobes and shelves without a single dramatic weekend, and the habit of asking "did I use this?" starts to shape what comes into the house in the first place.
There is more to learn on this subject, and the linked website goes into greater depth. Treat this article as an introduction rather than the final word, and check any important decision against up-to-date, reliable sources before relying on it.
If you try any of these ideas, start small and adjust them to your own situation. What works for one person will not suit everyone, and it is fine to keep only the parts that help. Writing down what you changed, and what happened, makes it much easier to see after a few weeks whether the effort was worthwhile.
The most useful step is usually the first one. Pick a single suggestion, try it for a couple of weeks, and then decide whether it is worth keeping. Small, steady improvements last longer than ambitious plans that are hard to maintain once everyday life gets busy again.