Visual Design
"Nice Gun."
Features
Lightning is 5 ft 7 in tall, making her one of the taller female protagonists. Looking at group shots though, she's still relatively short and scrappy. Her hair color appears to be strawberry blond and her eye color is a blue-teal-grean shade that varies depending on the image you're looking at. Just as she is versatile in a battle, she is also versatile in visual interpretation. Those who cosplay or draw artwork of her can choose to depict her more realistically (with lighter pink-blond or auburn hair) or in more of a fantasy style (with bright pink hair).
Like Ashe, the main female character in Final Fantasy XII, Lightning's design has gone through a lot of changes during development. See the image to my right for reference. Lightning's early design features red hair and a lot of strong, deep facial features. It closely resembles Nomura concept art. The final version, however, made her much more feminine. Her hair color was lightened to a pale pink, a smaller nose, rounded mouth, and a curved eye shape and a less of an eyebrow arch.
Clothing
She wears dark brown turtleneck under a white soldiers uniform top. The white uniform has a plethora of light brown leather belts and buckles, a common characteristic of designer Tetsuya Nomura. She wears a brown, belted mini skirt with black shorts/tights underneath (You can clearly see these shorts if you zoom up on her ingame). Her slim, red cape (my favorite part of her design) is attached to the brown straps on the back of her uniform. The green shoulder plate on her left shoulder have yellow marks that indicate her military ranking. She has slate blue, fingerless gloves with gold plating abve the knuckles, and a black sleeve on her left arm. Her boots are below-the-knee height and brown leather with metalic accents.
FF13's outfits are great in that everyone actually carries the weapon they use on their field model, with the except of Hope who sticks his boomerang up his butt. For Lightning, this means the gunblade holster that she hang from her hips. After battle, we often see her collapse the gunblade into its gun form and place it in the holster behind her. She also has a storage pack that hangs from her waist and left leg, making it more plausible that they are carrying around accessories, components, and potions.
Accessories
Lightning's weapon is a gunblade. On her initial weapon, the Blazefire Saber, she engraved the phrase "White Flash -- Call Upon My Name" - a self-reference that Light is a little embarassed to point out (as seen in Episode Zero when Lt Amodar tries to show off her weapon.) The gunblade is designed as a dual weapon in FF13, being able to transform between a Gun-mode and a Blade-mode. The weapon primarily resembles a long blade, and the blade portion folds back when it collapase into a gun. In each mode, the weapon function exactly as it sounds, as either a long sword or a basic handgun. This differs greatly from the gunblades that debuted in Final Fantasy VIII. In FF8, Squall and Seifer's gunblade were primarily swords that had a trigger at the handle - they did not shoot projectiles, rather, the triggers created tremors through the blade that dealt additional damage.
Lightning wears a lightning bolt shaped, silver pendent around her neck. Naturally, Square capitalized on this and made jewelry merchandise that looks like the necklaces FF13 characters wear. I want one. :< She also has the lcie tattoo on her chest. This mark is never seen ingame though. Light and Serah have matching dark leather armbands on their right arms.
Her Grav-con unit allows her to manipiulate gravity in a small range around her body. She uses this on the Purge train to attack while standing on walls or ceilings. She also uses this device to jump from great heights, removing gravity at the point of impact, so that she has a safe landing.