Rehearsal is a critical component of preparing to give an oral presentation, yet it is frequently abbreviated, performed in ways that are inefficient or ineffective, or simply omitted. We conducted an exploratory study to understand the relationship between the theory and practice of presentation rehearsal, classifying our qualitative results into five themes to motivate more structured rehearsal support deeply integrated in slide presentation software. In a within-subject study (N=12) comparing against participants’ existing rehearsal practices, we found that our resulting PitchPerfect system significantly improved overall presentation quality and content coverage as well as provided greater support for content mastery, time management, and confidence building.