Most people just plain have too much stuff. Do you really need 12 potholders and two potato peelers? What about the book you read once 8 years ago (there is always the library,) the old VHS tapes filling your bookshelves (there is always Netflix,) or the shoes that hurt your feet too much to wear - but darn
Keep a donation box in an easily accessible place at all times (mine is right by the door in my garage.) When it gets full, drop it off and start a new one. Keep a set of basic cleaning supplies (all purpose, scouring power, soap) in every bathroom and in the kitchen, and a stash of cleaning rags.