Lolita is a Japanese street fashion inspired primarily by the clothing and general aesthetics of the Rococo and Victorian periods. This fashion movement started in Japan in the 1980's and has evolved greatly since. Nowadays Lolita Fashion has grown to be relatively popular all over the world. Relatively popular for an obscure Japanese street fashion, that is.
A Gothic Lolita outfit like all Lolita styles, is very modest in today's standards. As with other Lolita styles a Gothic Lolita outfit can usually be recognised by the bell-shaped skirt, and puff-sleeves. A Gothic Lolita outfit is usually comprised of black or rich dark colors such as burgundy, purple and navy. It is common for this style to involve details in complementary or contrasting colors, such as the infamous black and white coordination choice.
Makeup for this style can range from a light natural look to a dramatic smokey eye with a dark red lip depending on the outfit and occasion. A common mistake by beginners that is worth mentioning is the use of black lipstick and whiteface. Both whiteface and black lipstick take away from the elegance of the lolita style and should only be used as stage makeup as a general rule.
Sweet Lolita is the most over-the-top style and includes aesthetics nearly exclusive to lolita. It is also the most child-like of the lolita styles, using many bows, ruffles and light colors to make up an outfit. The most common colors used in a Sweet Lolita outfit are pink, white, and powder blue, but an outfit can be made with nearly any pastel or plaid (or nearly any color at all as long as it is not neon).
Common motifs in Sweet Lolita are toys, strawberries, cherries, cakes and candies, hearts, polka dots and flowers. Prints inspired by fairy tales are also quite common.
Light, natural make-up complements this style. Teased out pigtails and bouncy curls are commonly worn by Sweet Lolitas.
Classic Lolita is the tamest of all the Lolita styles as many Classic dresses could pass for a garden party, church or summer dress. Unlike Sweet Lolita that is about looking cute, Classic Lolita is about looking classy, and harks back to Lolita fashion's roots in Victorian fashion, taking inspiration from the floral patterns, and the sense of elegance of the era; bold colors aren't normally found in Classic Lolita clothing.
Unlike the other styles of lolita, many Classic Lolita skirts have an A-line shape instead of the normal bell shape.
There are many more styles of Lolita, if you're interested there are a lot of websites with information on lolita and various styles.