A closet is more like a walk-in pantry. A dressing room with cabinets, fireplace, vanity table, etc., is very nice, but a storage closet is basically a storage closet and has the same parameters:
1. No windows. Natural light is great to see by but even worse for clothes than for food. Clothes are meant to last longer.
2. Consistent temperature. The HVAC can do a number in your closet, trapping heat or a/c. Having some way for the air to circulate, especially the a/c which can also be damp, is essential.
3. Humidity control. As stated above, damp isn't a friend for your clothes. Nor is bone dry. 50% humidity is ideal for textiles. Too much damp can weight the fabrics down and cause sagging, as well as promoting growth of mold and mildew. Too much dry and the fibers loose their suppleness. They feel scratchier and wear faster, and the little threads in the cloth can break.
4. Correct storage. Creases aren't good for most cloths. Hanging isn't good for some. A combination of hanging and shelf/drawer storage is ideal. Sweaters do best folded but not stacked. Pants are happier hanging from one end or other (depending on the construction), but can be draped over a rod (hanger or built in) without suffering too much. They do take up more space that way, however. Jackets must be hung, dresses and skirts should be hung unless they're made of a stretchy knit. Scarves and shawls should be draped over a rod or rolled on a tube to prevent creasing. Shoes that aren't worn very often should be in drawers or boxes to keep them from getting dusty and marred.
5. Space efficiency: Eye level is great for choosing clothes, but you can maximize your space better if you double hang and put tops as high as you can conveniently reach them, and either more tops, or skirts/shorts/doubled pants below. Long hanging storage is necessary for dresses and gowns, and best for suits. Suits can also be hung on double rails if the pants are doubled. Drawers/boxes of rarely worn shoes (ones that go with a particular dressy outfit and the like) can go on shelves above the hanging things. Keep a small step stool in the closet to make access easy. Handbags can go on open shelves, but it's nicer to have a door, also to keep out dust. A clear door can remind you to use them. Lazy susans can work as well in corners as in the kitchen. You can have all shelves for shoes and bags, or use a section for pants clips, tie hangers, scarf rolls, etc. Ties do best on tie hangers (bars with little rods for the ties). These only work if they're somewhere that won't be squished. Otherwise they're nightmarish. The inside of a cabinet door with the shelves set back is a good place. Belts work well on pegs, again, placed somewhere they won't get squished.
6. Smalls, undergarments, hosiery, gloves, soft hats, etc., are best in drawers, though work in baskets. It's nice to have a hamper or laundry chute right in the closet. Structured hats are best kept on forms in cabinets. Barring that extravagance, hatboxes are best. They can be stacked/shelved in hard to use corners. Don't forget the labels.
7. Daily wear. Include some storage for the stuff you constantly wear around the house. The hoodie you always put on when you get home. The old running shoes. Or a small wardrobe of sweats, little dresses, or whatever you wear when you're not "dressed". Make it really easy to access with room for house shoes and house sweaters/jackets, including hooks for that which you've taken off and intend to put back on. If you have it all easy to get at and organized these bits are less likely to decorate the rest of the house (if you have sloppy-lazies) and makes it easier to just pop into the closet and put off your good clothes. Also have a "current" spot for better garments that might have been worn slightly but will be worn again before cleaning. This can be a valet, small rack, or hooks, but should have hangers so they can be stored properly so as not to lose their shapes or get wrinkled.
8. Maintenance. I mentioned the hamper, but it's also nice to have a place to put dry cleaning, both going out and coming in, along with a pad to write down what you're sending to the cleaners and to check off as you put the fresh cleaning on proper hangers. Even better would be to have room for an ironing board right in the closet or dressing area, though I've never achieved that. :)
Sorry I don't have any pictures. I have or have had most of the above. My current closet came fitted, but it's not pretty. Just plywood. It works though.
Q