The most immediate measure of your teaching abilities is your students' response in class: if they start doodling frantically, yawning, or talking among themselves, if their numbers dwindle noticeably as the term progresses, if you are distracted from your grand orations by the sound of snoring.... you may be justified in suspecting that your presence is not as compelling and charismatic as you have believed. On the other hand, sleeping, snoring, absenteeism, and scuffling seem to be a way of life among many undergraduates, and are not necessarily any reflection on your abilities as a teacher. If you do feel that you are doing something very wrong, one way to find out for certain is to invite a neutral observer to one of your classes. Another TA, the professor in charge of the course, or a representative from the Instructional Development Centre could be asked to do this for you. Alternatively, you might have your session videotaped, so that you can observe your own behavior. Finally, you can collect some additional information through student evaluation of teaching.
Another TA. A fellow teaching assistant is the least threatening and least obtrusive observer. Your students are unlikely to notice a colleague and will behave more naturally. The TA may afterwards be able to point out to you any basic flaws in your teaching such as speaking too softly, asking the wrong kinds of questions, or using the wrong kinds of material.
The Professor in Charge of the Course. The course instructor or coordinator may want to sit in on one of your classes at some point during the term to see how you are doing. Your supervisor will try to remain as inconspicuous as a professor is able by sitting quietly at the back of the classroom, and will not interfere unasked with the conduct of the class.
It is a good idea to inform your students a week in advance of the professor's visit, and make it clear that they are not "on trial"; if anybody is, you are. After the class, the professor will discuss with you an estimation of your "performance", and perhaps make some suggestions that would improve your teaching.
The Instructional Development Centre. The Adviser on Teaching and Learning in the Instructional Development Centre is available, upon request, to observe teaching assistants or faculty in the classroom. A brief written report is provided, and is followed up by an informal consultation concerning your teaching. These services are completely confidential.
Having Your Class Videotaped. If you want to observe your classroom demeanour for yourself, you can have a class session videotaped. Talk to the graduate studies office in your department. If they do not have the equipment you require, the Instructional Development Centre can help you to make arrangements with Queen's TV.
Student Evaluations. At the end of the term, a course evaluation questionnaire will be administered in most courses. This usually asks students to evaluate the instructor in terms of teaching effectiveness, availability outside of the classroom, marking of papers and examinations, etc. Often these evaluations only cover the professor's performance and neglect to evaluate the TA.
If you wish, you could conduct your own evaluation halfway or a third of the way through the term. This is an especially effective way to obtain feedback from students so that you can identify what is working in the classroom and what needs to be improved. Be sure to share the results of the evaluations with the students, and to tell them what changes you plan to make in response to their feedback.