1. Have realistic expectations. Small children are usually not able to sit perfectly still and follow directions and smile a natural looking smile, all while looking straight at the camera. It doesn't mean that the kids are bad, it just means that they're kids.
2. Give them something to do. If you say "Hey, let's go out and take some pictures" you'll probably be answered with groans of protest. But if you say, "Hey, let's go outside with your skateboard!" then you might get a little more cooperation! You could not only take pictures of the child riding it, but holding it, sitting on it, or working on a trick would all make for some really cool photos! And these pictures will tell so much more about your subject than just a "sit there and say cheese" photo.
Just try to think of things they can do that will work well for pictures. It can be a big or a small activity. Here are some ideas: fly a kite, play an instrument, go picking in an orchard, read a favorite book, climb trees, pick dandelions or other flowers, have a picnic, tend or harvest a vegetable garden, make cookies (if you have good lighting in your kitchen), play croquet, etc. There are so many possibilities!
For these photos of my kids, I had them pick the tiny peaches off our baby peach tree. Click to view larger :)
3. Work for a REAL smile. For almost all kids, simply saying "smile" or "cheese" will get you an awkward expression. If you want a real smile, you're going to have to work for it. Break out your crazy dance moves, potty talk, or have them imagine their dad in a pink fluffy tutu! For older kids, asking about the opposite sex usually brings out a cute little smile. And the really little ones like to sing songs. For extra silliness, replace a song lyric with some kind of crazy word.
4. Be nice. Everyone, even kids, appreciate a kind, patient demeanor. And sincere compliments will help the kids to feel good about the picture taking process. Your attitude is the key to keeping the stress level as low as possible.
5. Keep it well timed and short. Photographing tired, hungry, or distracted kids can be frustrating for you AND for them, so choose a time of day where they'll be happy, well rested and fed. And remember that their attention span is usually pretty short.
These tips have worked great for me throughout the years and I hope they'll help you get some great images of your kids that you'll always treasure!