Although mounting research evidence suggests that dialogic teaching correlates with student achievement gains and with high levels of student engagement, little work in English education addresses the challenge of supporting new teachers in developing dialogically organized instructional practices. In a design-based study, we examine a curricular intervention designed to cultivate development of dialogically organized instructional practices, defined as instruction that provides students with frequent opportunities to engage with core disciplinary concepts through sustained, substantive dialogue. The curriculum invited secondary English teacher candidates to repeatedly enact dialogically organized instruction and to receive feedback from peers using video and Web 2.0-based technologies across a year-long student teaching internship. In English methods seminars, eighty-seven participants from two cohorts generated over 300 five-minute video clips, associated planning documents, transcripts, and reflections. We coded documents for student participation, evidence of planning for dialogic instruction, and classroom discourse variables associated in previous research with greater student engagement in substantive classroom interaction. We find that those who planned for dialogic instruction using dialogic tools were significantly more likely to have higher ratios of student utterances in relation to teacher utterances. The use of dialogic tools--conceptualized as those practical tools mobilized in teacher planning and practice with potential to mediate dialogically organized instruction in a given classroom situation--explained more of the variance in student participation than did any other factor. Attention to such tools may help English teacher candidates enact dialogically organized instructional practices. (Contains 10 tables, 1 figure, and 15 notes.)