i don't often go to 'clubs' anymore, although when i do, i go to upscale ones only, but i do often go to expensive restaurants that often have lounges in them.
Obviously, good music is a must, but so is good food and drinks- think creatively.
Have areas that are quieter than others, for people who want to hear eachother vs. people who want to dance.
theme nights- 60's, 70s, or 80s.
latin
techno
marti gras
if you're going to have tv's, which i would, put on stuff to match the theme. have dinner or drink specials named to match too. and GOOD, awesome lighting.