This document discusses focus-on-form instruction for teaching linguistic forms. It defines focus-on-form as treating linguistic form in the context of performing a communicative task, as opposed to the more traditional focus-on-forms approach where forms are taught sequentially. The document describes two main types of focus-on-form - planned focus-on-form using designed tasks to target specific forms, and incidental focus-on-form where forms are addressed naturally during communicative tasks. It argues that focus-on-form is more effective than focus-on-forms for developing learners' ability to use forms communicatively.