Hey man, the difference is not in gaming them, it's in your attitude towards gaming them... you have success with average looking targets because you don't think too much about having success... with a hot chick you are thinking to yourself "OMG, I am about to close this hot chick, better not screw it up" and that's when you screw up
Get a habit of sarging ONLY the hot chicks and you will get used to be in their presence and less nervous about the outcome... think about it this way, when you approach a girl that in the club looks like a 9, most likely when she is wearing no make-up or club outfits she's a 7.5 keep that in mind, and your attitude towards her will change...
There are some technical differences between approaching a 9 or a 7... more negging, less physical attributes compliments required for the hotter chicks that for the less attractive ones... but my guess your SP has rather to do with your attitude than with technique... Good luck!