This would be useful in a semi-professional environment, where full-on tactics wouldn't be feasible.

For example, I was looking at a girl's drivers license today- smoking hot chick, but her ID had a picture of her looking not even close. This chick was around 26, and her ID made her look like she was 40, no joke. I handed it back, and she jokingly said "I'm sorry you had to see that". It caught me off-guard, but I responded that she looked much younger now than in the picture. She looked at the picture again and said "Oh well that's true, I had no makeup on in this picture." Based on her response, I don't know if my comment came across as a compliment or not (still not sure) so I told her "it's not just the makeup, you look thinner too".

I was being sincere in both my responses, but I always find it very hard to compliment a girl, when comparing her to how she used to look before.

The reason I'm not sure if my response was taken as a compliment, and the question I would like to ask is, do girls like it if you compliment them and say something like "wow you lost some weight!"? Or would they take it as thinking they never were overweight before but apparently I thought so. Same reasoning as when I told her she looks younger now. Some girls may think "Well I don't think I looked THAT old in that picture" hence her response justifying it, saying she had no makeup on in the picture.

I really appreciate any responses, as this has always been an area I tend to stutter in.