Learners are often asked to create an interface as part of their course. For example, they could be asked to “create a calculator”, “develop a stopwatch” or “develop an image processing app”. But students often struggle to know how to start. At the same time, teachers want their students to think critically about their assignments and plan how they will build an interface. We have developed, and used for two academic years, a structured “critical thinking sheet (CTS)”. It is a method to help students consider a problem from different views, and help them critically consider different aspects of the task. The sheet gets the learners to (1) sketch the solution, (2) explain the challenge, (3) detail system components, (4) list algorithmic steps, and (5) explain next steps and issues of implementation. In this paper we introduce the sheet, explain how we have used it, and discuss learner experience.