As everyone else has said, do at least one run-through beforehand.
Speak slowly, and project.
Make sure you have all the items you will need, together in one place, well beforehand. Nothing like having to run off 5 minutes before initiation because you forgot the *ahem!*
If the initiates' names are read, be sure you know how to pronounce everyone's name.
<hijack> Y'know, it's a good thing that fraternity secrets website has gone away - otherwise I'd be wondering how long it would take before KD's super-secret dues-collecting ritual would be posted
</hijack>