Too much stuff

I have too much stuff (plants, ornaments, paintings, clothes), but I remember how I got every bit of clutter and just find it very hard to let go of them. I have moved things around and chucked some stuff out. But the majority of it remains. I would like to tidy up the place and would start by with living room. That would be my plan if I had to chose a new years resolution, but I can’t suss out how to get rid of more things!