If a girl reminds me of someone, I sometimes use it as a compliment in mid-game. I want to share you my thoughts about giving the 'you look like' compliments to a HB.

You should never compare a HB to a extremely hot public person. Or if doing that, some negs considering that comparison are a requirement.
Also, never compare HB to weird looking public HB (e.g. Christina Ricci), things can go batshit crazy .
And, instead of comparing the HB to a celebrity HB, try comparing some of her details again with a joke or a neg, e.g. if a HB has beauty spot, it generally works to tell her that you like her Cindy Crawford-alike beauty spot, even if it's sooo 90's.

Anyway, do you have any positive/negative experiences on look-alike thing?