Children these days are far less self conscious than when they had to sit still for a ‘real camera’ to be pointed at them.
When I started, a roll of 24 negatives to be taken and developed cost about £5 (the equivalent of £10 now) but since the advent of mobile phone cameras, anyone can take a mass of half decent shots of children, and happily throw most of them away.
I take photos of children with my phone all the time, but if I want a special photo, I rely on my Canon camera and try to remember all the old techniques I had to learn at the start of my career.
Candid shots are lovely. You need to be ready to snap it when you see it, which might take some patient waiting. Or you need to engage with the child to look your way, and then the trick is to either be very quick on the button or manage to stay engaged with the child, so that he or she doesn’t turn. Interesting child chat often pays dividends.
If a child gets bored and won’t play ball, then you might as well give up. Candid shots on the other hand present themselves and look fully natural. I never say “Look at the camera”.