Hadley Freeman in the Guardian was asked recently what is ' the safest way to compliment a lady?'. ( Read it here).
The question is revealing. It shouldn't be about what is safe, but what is right.
She has certainly got it right in identifying some of the things that should not be said: ( 'that dress makes you look pretty').
But I am less convinced of her recommendation. Yes, it may be ok to say 'That's a nice dress',. Or 'that colour really brings out the colour in your eyes'. But in my humble opinion neither of these are likely to pass muster.
Because they sound like a rehearsed response. Unless the male in question has a track record of paying attention to others ( perhaps a loaded question) , and a track record of comment and compliment, this is going to sound anything but spontaneous.
Ok, it's difficult for men. So many ways to get it wrong. It's not surprising that steering through these troubled waters results in something anodyne.
The real answer is simply 'You look fabulous'.
But it has to be said unprompted, and with spontaneity.
There may well have been time for a couple of martinis before being called on to say anything. That's what the martinis are for.