Not everyone likes to get their picture taken (me emphatically included), but the trick to shooting happy portraits is to make your subjects look like they're having a grand time. And the secret to that is getting them to smile--and not just a 99-cent fake smile for the camera, but a genuine happy smile. The best way I've found for doing that is to have someone else doing the dirty work for you--preferably someone that your subjects like and have fun being around. In this case is was the father/grandfather who was kidding with the three women just a few feet off camera. By having someone else interacting with them, as opposed to you saying, "OK, smile" it gives you a chance to watch for nice moments and keep your face pressed up against the viewfinder (or looking at the LCD) and paying attention to camera controls. Also, it helps if you're shooting from a slight side angle because then your subjects are interacting naturally with someone off camera and looking directly at them rather than into the lens. By the way, all outdoor portraits work best when they're shot in open shade with just a touch of flash to open up the face. If you set the white balance to "cloudy weather" it will warm the flash up nicely too.