Recently I got to shoot a 1st birthday party for Miraj Khair. Any party for children is always fun. Contrary to the beliefs of most parents, you don't actually need much entertainment. A group of children will always find a way to entertain themselves.
The party was in Byfleet Village Hall in Byfleet, Surrey. It's a typical village hall in that it isn't particularly well lit. When photographing children, who naturally move around a lot, it is important to make sure that your shutter speed does not drop too low. I always try to keep it above 1/60s and higher if they are active. If your shutter speeds drops too low, you will end up with blurry photographs and you can't get away with it by saying it's 'artistic blur'!!
There are a couple of ways to do this. I raised my ISO to around 800 for most of the images and I also shot at a lower aperture, which equates to a larger aperture. The higher ISO made the camera sensor more sensitive to light and the lower/larger aperture allowed more light in. Both of these changes kept my shutter speed high enough to prevent blurring.
I also used a flash occasionally, which helped to freeze the motion.
To learn more about ISO and aperture, you can read the following posts: