If you are asked this question, one of the first things you will want to define is what 'traditional' means to the interviewer. This can have very different meanings in different contexts, so spare yourself from assuming a good answer by clarifying upfront. Often, 'traditional' components of a wedding include some sort of religious or ritualistic element, such as prayers or songs. Once you have a clear understanding of what the interviewer means by 'traditional,' then consider how you will work with the couple to ensure that they are touching on all of the components that they find important to them. They might want certain prayers to be said at certain times, or they might want all of the components of that 'traditional' wedding without any prayers or religious affiliation. When it doubt, lean on the couple for direction on what they find most important to them.