I am a bit confused about what you are hoping to do as a career. Are you planning to be a teacher? Do you want a TA job to see whether a teaching career is for you? What future applications are you planning? What sort of work experience are you looking for? A couple of weeks or a regular commitment? Are you looking for a TA job after or during your degree? Sorry I can't offer you any real advice as I am not sure exactly what you need to know.