Study the martial-art form ba gua zhang. This name literally translates to "eight-trigram palm," which refers to the eight animals associated with this style: lion, snake, bear, dragon, phoenix, rooster, qilin and monkey. Ba gua zhang incorporates circular, whirling motions; "circle walking" is used as a training method so that the student learns to move and change direction without losing momentum. Aang the Avatar was born into an Airbending tribe, and though he must learn all of the elements, he favors Airbending; therefore, ba gua zhang can be seen when he bends.
Practice tai chi, the martial-arts style on which Waterbending is based. Tai chi focuses on the internal -- channeling and focusing one's energy; the student of tai chi learns to pass attacking energy through the body and channel it outward to defend himself. Tai chi is also a healing art; in the Avatar series, Katara teaches Aang the ways of Waterbending, and he learns to become a healer as well as a fighter.
Learn the hung gar style of kung fu, which is the martial-arts style on which Earthbending is based. Hung gar focuses on deep, low, strong stances, which are meant to connect the student to the Earth on which he stands. The more connected to the earth, the more powerful his stances and moves will become. Toph, Aang's Earthbending teacher, is blind and utilizes the Southern Praying Mantis style, which is a variation of hung gar.
Practice the northern Shaolin style of martial arts, upon which Firebending is based. The Northern Shaolin style dates back to the year 527 A.D., and many martial arts trace their origins back to this form. Northern Shaolin uses sharp, long, aggressive movements that involve extending one's body to attack. Zuko, the banished prince of the Fire Nation, becomes Aang's Firebending teacher; the northern Shaolin style can be seen in his aggressive, driving attacks.