One possible approach is: If you don't need something, throw it away; then you have an "easy" solution for given thing not cluttering your home anymore.

A similar but less extreme approach could be to buy a lot of stackable boxes and put everything there, and only take out things that you really need at some moment. After some time the things you didn't need would naturally stay in the boxes.

This could solve some of my problems; I don't know if your problems are of this type. Now that I think about it, I would have to do some research about a good system of boxes (big boxes for large items, small boxes for smaller items, and a system to put them all in one place), but the impact on my home could be great. I had a suspicion for a long time that the storage system has a strong impact on how the rest of the house looks, but I didn't spend time researching a good storage system.