Nice composition, but would suggest putting the sun more behind your subject(s) - stops them squinting, and gets a nice backlit effect. Also if you wear a white top or use a strategically placed bit of white card (and an assistant) you can reflect a bit more light into their faces which will also give them a decent catchlight in their eyes

(See below)

This was a shot I took of a neighbour's daughter a few years ago when I was doing Black & White "Old School" photography before computers so it's almost 20 years old.
