Get Rid of Something You Don’t Need

This kind of goes along with the decluttering one, so maybe you can combine them! Got a pile of magazines you’re not reading? A kitchen gadget taking up cabinet space that you haven’t used in more than a year? A craft project that you’ve been “meaning to get to” for like, 20 years?
Put on your stern face, look that object in the eye, pick it up, put it in a box, or a bag, or a backpack, and take it to your nearest thrift store to donate! Think of what other fun thing you can clutter that empty space with!