Writing is essential for communication in literate societies, and its successful acquisition and development is central to academic achievement. Beginning in early childhood, preschool-age children gradually develop componential skills within the domains of handwriting, spelling, and composing that ultimately enable them to translate thoughts and ideas into printed words to convey a message. Previous research has largely focused on teachers' practices in the general classroom context. In this study, we applied a fine-grained approach to examine preschool teachers' instructional practices for supporting children's early writing skills in a dyadic (i.e., one-on-one) context. The key aims were: (1) to describe teachers' supportive strategies for handwriting, spelling, and composing within a dyadic writing task; and (2) to determine whether teachers' supportive strategies varied according to the domain of writing they addressed. We asked thirty teacher-child dyads to complete a picture description writing task, and used a researcher-developed coding scheme to document teachers' supportive strategies. Descriptive analyses revealed that teachers frequently used directives, modeling, and closed-ended requests, and that there was wide variation in teachers' supportive strategies for writing, Moreover, teachers' instruction primarily focused on spelling and composing, and less so on handwriting. Accordingly, our findings help to complement and extend the extant literature regarding teachers' writing practices by providing a detailed description of teachers' strategies to facilitate children's writing and demonstrating the ways in which these strategies vary within a dyadic context.