In my work as a pro photographer I would guess that a good 70% of my images are of children. As a result I have discovered various methods of achieving the completely natural images that people love. There are many things to remember when trying to capture children's images. There are some methods that work and some that don't, here are a few hints that I have learned along the way.
Don't rush into things.
Children can be very shy at first and it takes a real skill to get a child's trust in a short period of time. I have an advantage over studio photographers in that I regularly shoot out doors (about 95% of the time). This means I can often meet the children at there home or a place familiar to them which makes it easier for the child to be relaxed. Having arrived at the location I set about gaining the child's trust and breaking down the shy barriers. This is essential if I want to capture the completely natural images I have made my name on. I never take the camera equipment in to the house straight away. I'll leave it in the car until I feel the child is ready. This also helps the parents to settle down. Its important to realise each little one is an individual and as such there is no hard and fast rule of how to treat any of them.
Timing
Not only is your timing of each shot vital but also the time of the day. Children normally run on a routine that involves sleep, food, drink and play. If you schedule the shoot to take place in anything other than a child's natural play time you are asking for trouble.
It should be fun for all involved.
If you want to capture natural expressions of joy (and who wouldn't) then the only way to achieve this is to make it fun. Depending on the age group the way this can be achieved differs but the basic guideline is, you play by their rules. Find something that would entertain them. For example for 0-4 year olds can be easily distracted with a bubble machine. For over 4's perhaps a kite or remote control car something that is both colourful and enjoyable. What you are aiming to achieve is a happy child who soon forgets about the camera and really is having great fun.
Don't force things
As any parent will tell you trying to get a child to do something they don't want to do is as close to impossible as things get. You can guarantee tantrums and tears follow if a child is forced into doing something they've decided they don't want too. The trick is to get them to want to do whatever it may be. Constant praise is all that should come from the photographer on how well they are doing. When I'm photographing children and for whatever reason they decide that they're not going to lie down / kneel or even stand I try once and then move on to something else. Ten or twenty minutes later I'll come back to the original pose and try it again, nine times out of ten this will succeed as the child has forgotten about not wanting to do whatever it was and we get the shot. As is mentioned before, you're playing by their rules.
Be prepared
You never know what each second holds when photographing children especially when you're outside. Many things can make fantastic photographs, throwing stones into a lake, patting a dog, throwing leaves all this and more. If you switch your camera off and put your lens cap on it's a sure way to miss fantastic unscripted moments.
I hope these points have made sense and will help you next time you take on the challenge of photographing children. I wish you fantastic luck.