I agree with @virmaior that finding a knowledgeable teacher, friend, or a class on "The Phenomenology" is really important in order to get the most out of the text. A basic understanding of Kant is absolutely necessary since Hegel is directly in conversation with the methodology of Kant in the work, particularly in the first half. Also, don't read the introduction until you finish the rest of the book!
As far as secondary sources, I found "German Philosophy 1760-1860" by Terry Pinkard really helpful in understanding some of the history of German Idealism and the context in which Hegel was working. The Pinkard and the text "Hegel and the Phenomenology of the Spirit" by Robert Stern were both recommended for a class I took on TPOTS and both of those texts were put under the heading "Beginning Hegel" or something similar. Since I was (and still am) "Beginning Hegel" I'll say that I found both those texts very useful in the class.
If you can't find a class or a teacher near you, then I would recommend at least reading it along with someone else and listening to J.M. Bernstein’s lectures on Hegel and Kant.