Three groups of typically-developing 6th grade students (total N = 62) each completed strategy-focused writing training. Using a combined lagged-group and cross-panel design we assessed the effectiveness of a sequence of four different instructional components: observation of and group reflection on a mastery model, direct (declarative) instruction, peer feedback and solo practice. Cumulative effects on written product and writing process were assessed at baseline and after each component. Findings supported the effectiveness of strategy-focused intervention: All three groups showed gains, relative to controls, in the quality of their written products assessed by both holistic and text-analytic measures, and a more structured and goal-focused planning processes. These effects were associated almost exclusively with the modelling and reflection component. Improved performance was sustained through other instructional components but there was no strong evidence that they provided additional benefit. This finding was replicated in all three groups, and across two different text-types