Notice the number of times each child is called on by the teacher. Research suggests children hear 520 negative comments to every 16 positive ones. When you teach, ask your partner or mentor teacher to give similar feedback to you. Notice whether boys are called on more frequently than girls. As you keep tallies of children whose names are called, look for any type of bias.
Teachers are human.
We want to be absolutely fair but there are always students who are easy to like and those who are difficult. Notice your teacher's introduction, expectation, value, and close. Notice the way your teacher establishes the management of instruction. Draw a diagram of the room. Notice if individual children have books checked out to them or if texts and materials shared.