@mismi,
Hey, mis,! Great topic! I am an avid organizer. Sometimes I'm better than others. My family, however, is not! They think I'm a "neat freak"! So, I try to have them put / keep things in the same places like counters, shelves in their rooms or our common family area. I've got some baskets and stuff depending on what it needs to hold. One of my favorite things is a cube organizer like this:
I use it for all kinds of things - shoes on the bottom (a pair for around the house...) homework, goo-gaws... It helps!
I have a filing cabinet in the office where I put folders of stuff we need to keep.
Toys in the basement also go in an organizer thing and colored tubs, sorted by what type of toy.
I also try to go through stuff every once in a while, and have them do so as well. Some stuff I have to do once a week, but it keeps the junk down! Plus I'm big on recycling & not keeping extra paper - mail, homework, artwork, whatever lying around. It's not perfect, but I do the best I can. Hope it helps if only just a little.