More good thoughts on preaching from Dominican (of course) Fr. Phillip Powell, here:

4. You know you’ve heard a good homily when…

…you are encouraged in your faith, strengthened in your trust of God,
…you are set afire to read your Bible, to read the Fathers,
…you are compelled to speak the Word to someone else,
…you are convicted in your heart to conversion,
…you are shown mercy and you show mercy in turn,
…you are deepen in the Apostolic Tradition and the authority of the Magisterium,
…you are sent out, given the proper tools, and convinced of success!