If girls give each other compliments over looks then it is often bullcrap. The way to measure if it's true or not is if there's a despairing "why aren't I as good looking as you" at the end of it, then it's probably true.
eg girl A says to girl B - "ggrrr I just love your figure babes, why can't I have a figure like yours!" (girl A thinks girl B has a nice figure and is wanting girl B to give her the magic secret tip) or another variation of it would be "ohh your make up is so gorgeous....where did you get that from/how did you do it?"
but if girl A says to girl B "don't worry babes, you'll find someone soon, you're gorgeous" (girl A doubts girl B will ever get a boyfriend due to the obvious fact she is lacking in the looks department, but is lying through her teeth to try and be nice)