Uncluttering and Organizing Small Space

Living in a shoe-box sized apartment isn't something most people call fun, but it could be practical. I'm no expert, but I have a few ideas on how to maximize space (by using modular furniture, wall shelves and making desks out of extra closets, nooks and crannies) I think that closets are unimaginative but could do so much more than they perceptively seem they can do. 
It will be difficult to house two women's clothing in one closet so I bought an IKEA closet organizer thingy on wheels with 5 big, spacious shelves and two wire drawer thingies that came separately but I clip on and put socks and things. 

Since buying the IKEA organizer, I've used it in innovative ways. I place folded shower towels ontop of the entire organizer and the hooks that protrude slightly to hold the whole thing up (it's approximately 5"3), I hang my jackets and bathrobe on it (the sides) and use the bottom shelve for miscellaneous items like photographs and newspapers. I will likely be putting all my clothes in here but I fear the Annex apartment will not be big enough to fit the IKEA organizer. If not, we will have to work with one tiny closet and just build more shelving and racks to house clothes around the bedroom on the walls and door.