For a while now, I have tried to make a habit of finding something specific to compliment my w on at least once a day - not "You look great today!" but "Hey, are those new jeans? They look great on you" or "I like the way you did your hair today, those curls on your neck are sexy".
I keep getting no response, like you say, or I get a "Thanks" with a small smile.
...But when we went through Retrouvaille, although the overall weekend was a disaster for us as a couple, at one point, when she was asked to say what she appreciated about me, she responded "well, I do like the way you compliment me recently"
So keep it up. She is noticing even if she isn't responding.
Me 42, W 39, S8, S6, S2 M 11y, A & ILYBNILWY 11/08 Walking away from a bad situation.