The shot is not bad. I quite like it. The flash is a little overpowered and is competing with the bright sun for the key light. The height and position of it seems to be level to the girls head, 3 to 4ft high maybe. This is creating an upward shadow on their faces which is not very attractive. The girls dress is a little over exposed in places. Her face looks a little hot too. You probably would have been better off finding the shade of a tree or something and taking the shot there. Otherwise drop the flash power down maybe a couple of stops and position it a little higher or better still use a light reflector and most of your lighting problems go away. :)