For a first pass I highly recommend reading the Ethics backwards, and only focusing on the collaries and the notes at the end of each section. Ignore the axioms and proofs for the first few passes through the book.

The content and notes at the end of sections are much easier to read and quite beautiful.

When I first read Ethics in the order presented I was deeply confused as to why Spinoza was considered the "prince of philosophers". After revising my approach he's rapidly becoming one of my favorite.

Despite it's presentation, the Ethics is much better approached in a very non-linear fashion.

edit: I also recommend Deleuze's Spinoza: Practical Philosophy. If you've read Deleuze's other work you may or may not be put off by this recommendation, but his work on Spinoza covers a lot of ground an is very readable.