I USED TO HAVE THE SAME PROBLEM. HOW I CHANGED IT WAS BY LETTING THEM ASSUME THAT IM THE SERIOUS TYPE, THEN OUT OF THE BLUE I SHOW THEM THE FUNNY SIDE, IF YOU CAN GET THEM TO LIKE YOU FOR JUST BEING YOU, THEN ANYTHING ELSE(SUCH AS HUMOUR, LOOKS, OR GOOD SEX) CAN ONLY MAKE THEM WANT U MORE.