A critical challenge for computer-based writing instruction is providing appropriate and adaptive practice. The current study examined three modes of computer-based writing practice with the goal of identifying those with the greatest learning and motivational value. High school students learned about writing strategies by studying lessons within the Writing Pal tutoring system and then practiced relevant strategies via essay-based practice, strategy practice, or game-based strategy practice. Students acquired strategy knowledge regarding their assigned topics, but there were no main effects of practice format. Similar findings were observed for students' beliefs about the value of writing practice. However, the effects of practice format depended on prior literacy ability in subtle ways. Essay-based practice appeared to be more effective for skilled readers, whereas less skilled readers benefitted more from game-based practice. Overall, "multiple forms" of practice opportunities may optimize benefits, although non-game forms of strategy practice are less preferable to students than game-based formats. [At the time of submission, this article was in press with "Journal of Educational Computing Research."]