I'm assuming you are talking about observing student teachers or teaching assistants.
Before hand, I normally prepare a checklist or rubric that I will be able to fill out during the observation. When I get to the classroom, I look around at the students to see if they seem to be engaged and comfortable. During the observation, I look for subject matter coverage, how well the teacher interacts with the students, appropriate use of technology (is the teacher showing films just to entertain or film up time or is there a point?), and how well students seem to be understanding the material. Afterwards, I look for students interacting with the teacher and also ask the teacher about any questions I though up (why did the teacher do X?) during the class. I may also check the course website before or after the observation.
Having been a student teacher observer as part of running a seminar at the university, I looked for several things. I looked for an agenda or some guide detailing what the students can expect to learn that day and if there is some quick way at the end of the time which assesses if the students understood what the concept for the day was even if they didn't all get it. I looked for a quick review at the beginning of the hour of the main point of the day before and how that relates to today's lesson. I looked for a good use of time which showed planning and an understanding of where students were on the scale of this concept. I looked for acknowledgement of all students by the teacher standing close to the entrance, greeting students, nodding at others, commenting on a new hairdo or the last hockey game they played or whatever it took to make students welcome and acknowledged whether beginning or end of the hour. After observation, I wanted to hear what the student thought, what they saw as the strengths of the lesson and the places for improvement. Then I wanted to tell them what I saw as improvements from the observation before, and what I saw as things which could be improved on. I think leaving a positive thought and ideas which they could work on were critical.
from what i seem to understand from your question is that what one should consider when observing a student!
you should consider the following:
- everyone is diffrerent
- each one has their ups and downs
- each person is unique in their own way!
- see the background they come from
then you should observe and observe them fairly and justly!!