Rastafari is more properly understood as a lifestyle, a philosophy, or a worldview. There are a diversity of beliefs within Rastafari, but here are the main things upon which all Rastas essentially agree:
-One God and one human family
-The teachings and philosophy of Emperor Haile Selassie I
-Respect and reverence for life (Rastafarians are adamantly opposed to abortion, war, and captial punishment).
-Roots and culture (i.e. knowledge of self through the awareness of African ancestry and heritage, as Africa is the cradle of civilization and the birthplace of humanity; but this is not African superiority, rather African priority. Special emphasis upon Ethiopia).
-Peace and nonviolence (although this is not a "hippy" peace, but rather an authentic peace that is predicated upon justice).
-Avoidance of politics, organized religion, and other manifestations of "Babylon's" system. (Babylon is defined by Rastas as any system or ideology that opposes the laws and love of "JAH," i.e. God).
-Reverence and knowledge of the Bible (Rastas believe that Babylon has corrupted the true meaning of the Bible, but that JAH will reveal its true meaning to them through idividual and collective "reasoning." Since JAH dwells within every man, every man can understand the Bible for himself if he is pure).
-Natural or "Ital" lifestyle. Most Rastafarians are essentially vegetarians, as it promotes life and doesn't involve killing. The dreadlocks are also a manifestation of the natural man.
OK, those are just a few things for now. It's a lot deeper than that for sure. Not all Rastas worship Haile Selassie. The largest "mansion" of Rastafarians is the "12 Tribes" which was founded by Dr. Vernon Carrington. He taught that Haile Selassie was not God, and that Jesus Christ alone was to be worshipped. Many 12 Tribes Rastafarians are also Ethiopian Orthodox Christians.
Much that has been written about Rastafari from an academic perspective is greatly misleading. Rastafari is very mystical, and efforts to categorize it as a cult or religion are erroneous. Certainly those that worship Haile Selassie are in great error; but their love for Haile Selassie provides a perfect opportunity to show them the Light of the Ethiopian Orthodox Church and the Light of Our Lord.