A closet is storage for a specific set of things, so the design should start with a count of those things rather than a picture from a catalog. Before we draw anything, we measure how many linear feet of hanging clothes you have, how many are long, how many piles of folded items, and how many pairs of shoes.
Double-hang sections are the biggest space-saver. Shirts, jackets, and folded-over pants only need about 40 inches of drop, so stacking two rods in one column doubles the capacity of that wall. Long-hang sections for dresses and coats take a full column, and they usually need less width than people expect.
Drawers beat shelves for anything folded. Shelves lose the back half to things you cannot see, while a drawer brings everything to the front. We typically put a bank of drawers at the center of a walk-in, with a countertop on top for a watch, a bag, or a place to fold.
Shoes go on angled shelves at a pitch that shows the toe, spaced to the height of the shoes you actually own. Boots need taller gaps; flats and sneakers can go tight. Accessories get pull-outs: tie and belt racks, a jewelry drawer with dividers, a hamper that slides out.
Every closet system we build is sized to the room, built in our Riverside shop, and installed floor to ceiling, so the top shelf and the floor space both do real work. A free in-home measure is where it starts.