In our new home I was finally able to have things in one place and leave them there for a while!
We had a temporary roommate who would be getting married the following summer. She and her fiance were two of my son's first babysitters when he was 4 months old. Our families are still close, if not geographically! She was so open to my "odd" ideas because of her impending marriage and because her younger sisters had not been babies in so long that she loved the experience of having a baby on-hand again.
Living Room
We set up the couch so that the child's table/chair set was behind it - in a private area of sorts.
The rest of the living room was set up so that nothing down low was off-limits for young children. We did slowly let up on this because children DO need to learn limits of what they can and cannot touch. So we'd leave something of interest and teach him, "No touch."
Basket of books for his use.
Now, we had a crowded living room, but that was from my non-Montessori days, when I did my own share of traveling and having things in storage; not knowing what I had and accepting gifts from well-meaning loved ones. When we moved into that apartment, I was finally able to have all of my belongings in one place at one time and truly figure out even what I owned - our large living room was cut in half by stacking ALL boxes ceiling high in one half of the room. I had 4 sets of dishes. Yes, they were sold off eventually. And I was further driven to minimize-minimize-minimize.
Bathroom
Under the sink: cloth diapers and wipes (I did not use cleaning solutions for the wipes - just water and a squirt of handsoap when needed)
Toilet lid rule: always closed when done
Bathtub: all shampoos and implements in one of those hard baskets in the corner, up high; child items in a cloth bag suction cupped to the side
Cleaning chemicals? We didn't really use any... toothpaste and such was kept in the cabinet; medicines and such shouldn't be stored in the bathroom anyway (moisture damages them) - so these were kept in the pantry closet, along with the all-natural cleaners we used.
Kitchen
Under the sink: small broom and dustpan; cleaning cloths
Lower cupboards: pots, pans; plastic storage bins (we had a lot of those at the time...)
Garbage bin: tall and narrow with a flip-over/swinging lid; we used shopping bags for garbage and all other shopping bags were stored in the bin, underneath the currently-in-use bag
Shelf for child's items: so the children could get their items themselves - dishes, cups, placemats.
Placemats: I found some solid color woven placemats at a thrift store and drew the shape of our dishes onto them, so that the children could set their own place at the table even at age 1. My son (age 7) still likes to use his placemat like that just for kicks.
Bedroom:
The roommate's room was off-limits.
Our room had the floor bed, stuffed animals, mobiles, the long floor mirror, and all other items (since most of my belongings were at that time still stacked in the living room!). In infancy this was all that was needed, since we did things together; or had baskets throughout.
Throughout
No shoes allowed. Children crawling on the floor do not need the crud that comes in off of the roads and sidewalks; I can handle what happens in the yards better (the earth takes care of some of it), but it still doesn't really belong inside.
Lower areas were child-friendly. So a child could safely explore without constant supervision (parents do need to blink their eyes! and use the bathroom!)
Upper areas contained the more dangerous things (chemicals, medicines, knives)
Each room had a basket appropriate to that room. So if I was in the shower, the basket in the bathroom might have a book or a textured ball or something else that he could play with while I showered.
In the kitchen, it contained kitchen utensils I could name for him while I was working in the kitchen.
The living room baskets (I had 3) would vary - one was for books that I rotated; one had a variety of "toys"; the other had religious items. As he used them, I would tell him the names of the items; sometimes show one way something could be used.
This lasted until about a year and a half - even by then we had already been phasing into toddlerhood........