The advice that follows was generated by some of the most common questions and concerns TAs express. This is up to you.
Some students feel it's easier to approach a teacher they can call by their first name.
Some students need to have an authority figure and calling the instructor by their surname helps to reinforce the student-teacher relationship. This too, is largely up to you and dictated by taste and finances. We strongly discourage sexually provocative clothing for teachers, but just about anything could be construed as sexually provocative. You will see the gamut of clothing styles, from suits to blue jeans. Women needn't wear dresses or skirts, slacks are fine.