It's what we do as conductors; it's where the composer and the performer search for one another; it's where our energy, creativity, skill, imagination, knowledge of the score, and understanding of the instrument (the chorus), all come fully into play. In my experience, I have found a rehearsal routine that varies only slightly from one situation to another. It begins with what I do before the first rehearsal.
The conductor's preparation
Score selection and study
The music I have chosen has to be intensely interesting to me so that I am eager to study it. When I study, I search for the music's essential features. Identification of these essentials is possible only through score analysis. The analytical procedure follows a hierarchy that starts with an overview (key, meter, voicing, form in the overall sense, text, etc.), goes next to the division of the large form (ABA, through-composed, etc.), the subdivision of each division into smaller sections, the breaking down of the subdivisions into groupings of measures, and, finally, the phrasing. All of these decisions are guided by a clear sense of harmonic, melodic, and rhythmic motion. Score analysis reveals the content of the music and guides me in shaping the rehearsal process.
Early in the preparation of the score, and as I discover phrase lengths, I insert marks to indicate breathing. Where possible, I assign rhythmic values to the breaths. All matters of phrasing are dependent on text, so the translation and correct pronunciation, with elision and International Phonetic Alphabet (IPA) symbols, should be inserted. Once I have made these decisions, the singers can transfer markings into their own scores.