The best way to make each set of characters stand out is to look at things through THEIR perspective -- how THEY view the world.
What would THIS person see and notice most? What would THIS person think about? What would THIS person compare to whatever he/she is looking at?
A heroine who's five feet two will have a different reaction to a hero's height than one who's five feet eleven. A heroine who's a cook will have a different reaction to a hero's physical presence than one who's a physical therapist. A heroine who sells perfume for a living will have a different reaction to a hero's aftershave than one who's ... well, anything else. A heroine who's a musician will have a different reaction to the hero's voice than one who's not at all musical.
See what I'm doing here? I'm looking at the hero through the heroine's eyes. What does SHE see, feel, hear, sense that's different from what any other woman would see?
The same thing works in reverse, of course -- what is there about our hero which makes him notice specific things about the heroine?
Let's talk about how you could make this work!