Well thought out questions are crucial to demonstrating your efficacy.
If you are unlucky enough to be observed by a non-science SMT member, the questions you ask and your response to the answers will enable you to highlight misconceptions at the beginning of a lesson and attainment during the plenary.
Make sure that you have a variety of open and closed questions. Ensure that you are clear about the purpose of the questions you are asking, e.g. to promote discussion or to elicit understanding as part of AfL.