Here is mine: Don't tell your gf she is attractive or looks nice, just another way of saying she is not butt ugly lol. Always use the superlatives in the correct order:
Cute: Attractive sweet in endearing way.
Sexy: Sexually attractive or exciting.
Pretty: Attractive in a delicate way without being truly beautiful or handsome.
Beautiful: Pleasing the senses or mind aesthetically, Gorgeous, Stunning are equal