Ooh! If it were for an ordinary lesson I've lots of ideas but for an interview? I usually just work with where their 'normal places' are, often find they're sat when I walk in , so don't want to waste precious time re-arranging them. Plus all the potential for problems, if they don't like the arrangement. However if they're lined up outside, easiest way is to ask them to line up in alphabetical order and then file in and seat themselves from the front. If it's a language lesson I've asked them to line up by first name / birthdate and make it part of the lesson, as they have to use target language to get themselves into order. Otherwise lollysticks ?