As Ruby mentioned already, do not swear at all. As soon as someone swears to me I'll make a mental note to remove them from the short list, unless everyone else were complete and totals retards.
Just try and be confident even if you might not be feeling it and it's always a good idea to sell yourself in regards to your past experience, just don't over do it because I can always tell who's talking shit to me when it's so obvious they haven't got a clue what I'm talking about or the question I asked.