A number of studies have examined the process and product of writing instruction under different conditions. Fewer studies have investigated the development of knowledge and its relationship to writing performance. While some writers may be able to draw upon knowledge of text in their writing, others do not possess this knowledge and yet others may possess the knowledge but fail to draw on it. This study explores the development of and relationship between declarative knowledge and procedural knowledge among a group of 36 Hong Kong Chinese ESL learners in a three-month university writing course. The interaction of awareness of writing effectiveness with writing performance was investigated. Subjects of high and low English proficiency were put in either self- or peer-editing groups. They wrote reflective journals demonstrating their awareness of effective writing of short paragraphs and complete essays. Results suggested that both awareness of and ability in effective writing were enhanced after the course. High proficiency students and peer-editing groups demonstrated greater awareness and performed better in the writing tasks. Knowing and doing in ESL writing were found to be significantly related among proficient and peer-editing groups. [Copyright of Language Awareness is the property of Routledge. Full article may be available at the publisher's website: http://dx.doi.org/10.2167/la365/0]