Single question surveys work better with lower level classes. Each student is armed with only one question which they have to ask each of the other students in tuen. One advantage of this method is that you can give weaker students an easier question and stronger students more complex ones.
Give each student their question, for example in a cut-up form (see example PDFs), or have them come up with the questions themselves and then decide who will ask which question. Students then circulate and ask the other students their question and note keywords and details down. They must also, of course, answer the question put to them by their interviewee.
When the surveys have been completed, have the students sit back down and give a report to the class about their findings. This could also take the form of a written report for homework, etc.