Understand the Haggadah and what is essential and what you can skip (especially if you have young children). Proof from the haggadah that Jewish sovereignty is a Torah concept. We first mention freedom from slavery (political oppression) and then from idolatry (spiritual oppression); learn which is more important.
Understand who's arguing and what are they are arguing about. Learn the difference between haggadoth in Israel versus haggadoth of the Exile. Hear how did they began the Haggadah in Israel--surprisingly with idolatory first--and why many Haggadoth don't finish the drasha of arami ovad avi.