I will practice here on my blog. Here goes....
Try and get your subjects to laugh. Have some fun it makes them look more natural.
Make sure that the sun is to the back of your sweet subjects so that they are able to see.
Feel free to change locations if you find that it is not working. Don't be scared to get that whole group to move.
If parents insist on coming to the shoot.... (which most likely they will) Instruct them at the beginning of the shoot that they are welcome to be there but it would help greatly if they would stand off to the side, not behind you (the photographer) kids tend to look at there parents for direction. You do not need 10 children looking in different directions. Example below.
Have a short meeting with them prior to the photo shoot. You can discuss Location, wardrobe, props. Have your clients look at your porfolio before hand. So that they are familiar with your style of work. DO NOT, under any requests, the day of the photo shoot start allowing the clients to direct you.... this is what will happen.
It takes about an hour (which goes quickly) to get about 10 - 30 good shots. So have fun and relax. If you are uptight your subjects will most likely be as well. You can do it.
A big Thanks to my models. My nieces, nephews & my kids. This was a Photograph for our parents anniversary. They loved it. Made my Mom cry.... (I am so mean)