Oh, for group shots there are a few things to keep in mind.
1. Stay out of direct sunlight, it's more or less impossible to get even slightly even light with that harsh light. Stay in the shadow, of shoot on an overcast day. (Clouds are wonderful softboxes)
2. Make sure everyones eyes are open. A tip to make that a bit easyer for yourself, is having everyone close their eyes and then open them on your count to 3.
If we're talking composition, I'm afraid I can't help you much, since I suck at it myself. My best tip would be to check out other group portraits and print some of the ones you like and bring them along as workprints
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