District 1 - Luxury
In the film, Glimmer and Marvel wore fuchsia-colored outfits that were belted out in sequins and feathers. The feathers and glamorous accessories made a statement about their district. Glimmer wore a headdress that lay flat against the top of her head, like a cap, and had then fanned out, like the feathers on a peacock.
District 2 - Masonry
District 3 - Technology
The silver outfits sported by the male and female tributes represent the intricate inner working of electronic devices. The silver mesh material was very shiny, and might have been meant to represent metal electronics.
District 4 - Fishing
District 5 - Power
The male tribute and Foxface (real name unknown) wore costumes that reflected light and shone whenever the tributes turned around. The glittering, eye-catching silver represents the color of wires and other power-like items. Their costumes represented a solar panel.
District 6 - Transportation
Covered in sparkly gold sequins and spectacular moon headpieces, the male and female tributes sported far-out costumes. They were "flying to the moon." It also represents that it takes time to travel, and that some people used to use the moon for directions.
District 7 - Lumber
The male and female tributes costumes represented folded origami paper. Their headpieces were sculpted to look like a professionally made origami (Though in Catching Fire, Johanna Mason says that their stylist is the biggest idiot in the Capitol and has dressed the District 7 tributes as trees for the last forty years).
District 8 - Textiles
District 9 - Grain
District 10 - Livestock
District 11 - Agriculture
Rue and Thresh were dressed up as farmers, so their costumes were full of plaid, puffs, and overalls. These outfits describe their district very well. They are both wearing silver headdresses meant to look like the grain seen on the symbol for their district.
District 12 - Coal mining
Katniss Everdeen and Peeta Mellark wore a black suit with a cape that was able to set on fire on command (The fire was synthetic.) This earned Katniss the nickname "girl on fire." During the fireball attack in the arena, she speculates that Cinna's beautiful costumes might have even brought on that particular torture for her. Their costume represented a piece of burning coal, the black jumpsuit being the coal and the flaming cape the fire.