"Shia", in his technical sense, originally indicated a person who followed Ali and preferred him to the other sahabah. It was not supposed to be a sect or a variety of doctrinal branches with different theological or religious views. As a matter of fact divisions were spread, the book "Firaq al-Shia" by Hasan Ibn Musa al-Nawbakhti, available also in English, mentions most of their ramifications. Nowadays the main surviving schools are the Zaydiyyah (Zaydis), the Ismailiyyah (Ismailis) and Ithna Ashariyyah (Twelvers).
With prayers for your success.