A good teacher practises formative assessment constantly on an informal basis through interacting with students and observing how they are going. At its most informal level, formative assessment can be a conversation between a teacher and a student. As this type of assessment is low stakes, there is less need to establish processes to ensure the reliability of the assessment. Assessment can be thought of along a formative/summative continuum. Teacher/student conversations are at the formative end of the continuum, and assessment used for qualifications is at the summative end. http://bit.ly/2MJUm2x

Feedback lets a student know when they are on track and where there are gaps. The Te Kotahitanga project used various forms of feedback in observing teachers: positive feedback academic, negative feedback academic, positive feedback behaviour and negative feedback behaviour.

Student voice is valuable feedback to the teacher. Students may not want to tell the teacher directly so this can be done through exit slips, Google forms, a neutral observer etc. John Hattie's 3 questions are valuable here. What am I/you learning? Why am I/you learning it? How will I/you know when I/you have succeeded?

There are more really useful questions teachers can ask students here