Black, white & any dark color such as dark red & dark blue clothing.

Silver jewelry 

Dying hair black, "stripped" blonde (white), purple and red. Also ratted out, hairsprayed, chaotic hair, hair extensions & a short A-line haircut

Wearing Religious jewelry such as ankh, the Eye of Ra, pentagram & crosses.

Wearing white foundation & black makeup.

Bondage & fetish fashion, such as leather, latex, vinyl, rubber & corsets.

Not exposing any bare skin.

Velvet, crushed and regular.

Capes and cloaks, usually opera-style.

Gloves, usually opera length, and velvet & latex material.

Fishnet either in shirts or tights.

Staying as pale as humanly possible.

Chokers such as a dog leash with spikes, a velvet ribbon tied around the neck or a bondage collar. 

40's style, thin, plucked eyebrows.

Chains & spikes.

Tattoos and piercings. These vary depending on the person, however it would appear the most common piercing is the tongue.

A leather jacket, black trench coat (DOES NOT MEAN YOU ARE IN THE STUPID "TRENCH COAT MAFIA", we have style as opposed to complete gun-happy morons), black vinyl jacket, velvet jacket or faux fur jackets.

White poet's shirts

Band paraphernalia. eg, t-shirts, stickers etc. 

Combat boots or Doc Martens, pointy toed shoes, buckle boots, high heels & "bondage boots".

The box. This looks something like a small lunchbox or old-style make-up case. Usually they are small, carrying only ciggies, lipstick, money & ID.

A fishnet shirt, vinyl pants, boots and silver jewelry. 

Makeup, skirts, corsets or heels (not a transvestite thing or necessarily homosexual), white shirts, black vests, black pants...stick with the basic black and you can't go wrong guys!

For girls, some common Goth looks are: 

A crushed velvet dress with either boots or heels. 

Fishnet shirt with a black bra underneath, with any of the following bottoms:

Long velvet skirt 
Tight leggins/stirrup pants usually velvet or vinyl 
Short Vinyl skirt