When interacting in class, teachers with low expectations tend to:

Wait less time for the student to answer a question.
Call on the student less frequently to answer a question.
Inappropriately reinforce an incorrect answer of the student.
Prematurely give the student the answer or call on somebody else
Withhold helpful clues and fail to repeat or rephrase the question.
Give briefer and less informative feedback to the student's questions,
Interrupt more quickly when the student makes mistakes.

NOTE: I recieved this information from Donnie Smith.