Lolita skirts are often very full, enough to fit a full petticoat under. They are usually either gathered or pleated, but sometimes they may be a circle skirt. They tend to sit at the natural waist and flare out from there. Most Lolita skirts are designed to hit either just below or above the knee.
However, some Lolita skirts that are inspired by other sub-styles, such as Victorian fashion or Fairy Kei may have a different shape to them, but these are uncommon and might not always be considered part of the Lolita fashion, whether or not they were released by a major Lolita brand.