1. Zoom in tight on your subject. This will help eliminate distracting things in the background.
2. Check your background before you take the shot to make sure you don’t have a lamppost growing out of the top of their head.
3. Turn off your flash. Unless you cannot get a shot without flash, it’s always better to turn it off. The flash on most Point and Shoot / Phone Cameras is very small and creates a very harsh look and the dredded Redeye. Put your camera into Portrait or Night portrait mode.
4. Take several shots. This is probably the biggest difference a professional photographer makes. It’s almost impossible to capture the right expression in one photo. Be patient and wait for the right moment and then take several shots.
5. Get down to their level and focus on the eyes.
And finally a bad photo with a great expression beats a perfectly exposed photo with a terrible expression every time. Avoid posed shots, have your camera ready, interact with the children and wait till the right moment presents itself.