Start with what goes in it
Not with a catalogue layout. Count what actually hangs long, what hangs short, what folds, and what lives in a box. Double-hanging short garments doubles capacity in the same width, and most people need far less long-hang than a standard closet gives them.
Built-in or system
Modular systems are quicker, cheaper and can be reconfigured. Built-in millwork fits an awkward space exactly, reaches the ceiling, and looks like part of the house. In an older Florida home with odd closet dimensions, built-in usually wins on both fit and usable volume.
Planning custom closets in Orlando around humidity
A closet on an exterior wall in this climate is the one place in a house where leather and natural fibres get spoiled. Custom closets here should be planned with a gap behind the backs, a vent or a louvred door, and no sealed cavity against the block. It costs nothing at design time and is the difference between storage and a slow mildew problem.
What custom closets cost against what they return
Less than almost anything else per square foot, and they return it daily. A fitted reach-in is a fraction of the price of a kitchen drawer bank and roughly doubles usable capacity in the same footprint. A walk-in fitted properly can remove the need for freestanding furniture in the bedroom, which is the change people actually notice.
Two things people forget
Light, because a dark closet defeats good organisation. And ventilation: a sealed closet on an exterior wall in this climate is where you find mildew on leather.