You can find lists on the forum of all the common interview questions. My husband and I just had our interview in Beijing this week. They asked him (applicant) questions about me and my work and our life together for about 1/2 hour, then they asked me (sponsor) similar questions to verify that I would give the same answers. Then they called us in together and said they believed our marriage is genuine and would give us the visa that afternoon.
As long as you and your spouse know about each other well you shouldn't have any problem with the interview.