Kill 'em with evidence. At the time my husband went for his interview, there were alot of horror stories about people being denied for lack of evidence. When, in reality, they had the evidence on them, but the consulate never asked for it. I overloaded Ahmed with piles of intricately organized evidence and made sure he knew to give it to the consulate, whether they wanted it or not. I dont advocate throttling the interviewer in order to get them to peruse the goods, but I would advise some polite pushing if the situation calls for it. Mind you, Ahmed's interview was a year ago, and things have probably changed. The officers seemed to change attitudes with the wind, so I cant say which one would be the most favorable.
Ahmed did note that having confidence helps, even if you dont feel it. He watched six people in a row get denied for assorted other visas, most of them speaking little or no French or Arabic and about as nervous as a cat under a rocking chair. Choose your best language, whatever it may be, for the interivew. Dont try to be impressive and do the whole thing in English if you know you're not going to be confident in it. If I recall correctly, Ahmed said they had officers who spoke French, Arabic, English, and Spanish, but again, things may have changed. Even though you're probably scared spitless, try to exude cool confidence. Also, ask them how the interview went, once things are finished. They will usually tell you yes or no at the time, and that often helps calm you down.
And isnt there a little cafe across the street?

If I remember, its something of a tradition for the interviewees to toodle over there for croissants and coffee while waiting for their turn.
And as okiegurl notes, dont be afraid to get your senator or congressperson in on the game. Dont wait until months have passed. If you're unsure about your interview at all, get on the horn and get those blasted reps in there to do something about it, ASAP!
Inchaa allah you will have a quick and painless interview and shortly a visa in hand