Originally, Hopi men didn't wear much clothing-- only breechcloths or short kilts (men's skirts). Hopi women wore knee-length cotton dresses called mantas. A manta fastened at a woman's right shoulder, leaving her left shoulder bare. Missionaries didn't think this dress style was modest enough, so in the 1900's many Hopi women started wearing blouses underneath their mantas. This style is still in use today. Men and women both wore deerskin moccasins on their feet. For dances and special occasions, women painted their moccasins white and wrapped white strips of deerskin around their shins as leggings. Here is a site with sketches of Navajo and Hopi clothing styles, and some photos and links about Indian clothing in general.
The Hopis did not traditionally wear feather warbonnets. Hopi men usually wore cloth headbands tied around their foreheads instead. Most men wore their hair gathered into a figure-eight shaped bun called a hצmsoma, though some Hopi men began cutting their hair to shoulder-length during the early 1900's. Umarried Hopi women wore their hair in elaborate butterfly whorls, while married women wore theirs in two long pigtails. The Hopis also painted their faces for special occasions. They used different patterns for war paint, religious ceremonies, and dances.
Today, many Hopi people still wear moccasins or mantas, but they wear modern clothes like jeans instead of a breechcloth... and they only wear legging wraps or kilts on special occasions like a dance.