Get in the club tell yourself I know the drill and get on wiv it
The only reason why you're different at work and at the bar/club is that at work you know the drill n just do it n u don't fear these ppl.
On the other hand at the bar at the club you look at that 500 pound gorilla that fits very nicely in that dress n u start getting nervous n thus u don't think of it as 'just a drill' anymore
like Hustler25 says everything you need to know about live/women is in rock n roll.
anyhow hope i was of some help mate
ps: for an extra confidence boost you could put some of your favourite upbeat tunes and jsut dance, or maybe if you're more intellectual remember a quote from a book or just do a few press ups