You're just brushing up against internet cynicism atm... Don't sweat it. IMO these forums tend to be a bit more oriented to day to day wear and clothing quality. Club wear tends to be more trendy, not generally as great a quality in terms of wear etc, and over priced.
Here's my general advice which may be a bit dated as a family man now ( 8 year streak as a DJ in San Fran / Producer / Audio Engineer ):
1) Confidence / attitude is better than anything else so wear something you still feel like yourself in
2) You're young so stay away from dress shoes... Boots are probably too hot for Florida. Roll classic sneakers ala Onitsuka Tiger's or Chuck Taylors.
3) Get a nice pair of dark jeans... This forum has tons of good advice on that department. I like Naked and Famous for the raw jeans department. However, since I wear dress shirts tucked in all the time, I have regular jeans to prevent bleeding onto the shirts. Just find a pair of Straight or Slim cuts. Stay away from Boot cut or skinny if you want the jeans to stay in fashion over their lifespan.
Do people wear dress shirts to these clubs? From the top up dress accordingly to the venue. In all honesty a trendy Boss buttoned up shirt would be hard to go wrong with for this type of situation.