If you want to use natural light head for a space with a large window or if you prefer to use artificial lighting, a simple two light setup, positioning one light slightly to either side of the model should do the trick. Plain backgrounds work well as it's the expressions we're interested in not the colour of the scenery. We used a studio background but a table cloth, sheet or wall will work just as well.
As you don't want your subject's face to be blurred, make sure you're using a quick enough shutter speed when shooting hand-held. If you're using natural light and are having problems with shake, stick your camera on a tripod. Watch your white balance too as you'll be putting these shots together at the end and if the white balance is right in-camera, there will be less work to do once you have the shots on your desktop.
Don't think this is something for just DSLR users either as when using natural light, a smaller compact will work fine.
When it comes to taking the photographs, don't linger on one expression for too long as if your subject thinks about what they're doing for too long it can look a little fake. You'll also find it's more fun to shout out instructions rapidly as it can sometimes go wrong, giving you the chance to capture your model laughing or pulling an expression you didn't expect. Have a list of ideas to hand, particularly if you're working with kids who need a little more instruction, but don't be too strict with it. Adding props such as food or a drink can work well, too.
If you want to create a triptych or other style of portrait collage, simply re-size them in your chosen software, check the tone and brightness, then pull all the images onto a new document, positioning them as you go.
You've read the technique now share your related photos for the chance to win prizes: Photo Month Forum Competition