I highly recommend "Theology and the Church" by Fr Dumitru Staniloae if you can find it.
From the back of the book:
In a fresh and masterly synthesis, rooted in the tradition of the Greek Fathers yet open to the legitimate concerns of contemporary Christian thought, Staniloae gives a dynamic presentation of the Orthodox doctrine of the Trinity as a basis of ecclesiology and anthropology. He assumes into a balanced theological framework the totality of creation, the world and human culture, by referring it to its ultimate goal: restoration and transfiguration.
The book is a collection of separate essays from Romanian journals so you can pretty much start at any chapter your interested in. Particularly, after reading the first three chapters, and especially the 3rd chapter, I came away with a much better appreciation and understanding of the orthodox expression of the Trinity. I would buy the book just for the 3rd chapter. Here's the chapter titles:
Chapter I: Trinitarian Relations and The Life of the Church
Chapter II: The Holy Spirit and The Sobornicity of The Church - Extracts From the Report of an Orthodox Observer at the Second Vatican Council
Chapter III: The Holy Trinity: Structure of Supreme Love
Chapter IV: Revelation Through Acts, Words and Images
Chapter V: Revelation as Gift and Promise
Chapter VI: The Orthodox Doctrine of Salvation and Its Implications for Christian Diakonia in the World
Chapter VII: The Problems and Perspectives of Orthodox Theology
