These tips are OK but my personal experience has been that for one, people hate it when you flash them a lot and the more images you take, the more disinterested and bored looking your group becomes. And the bright, evenly lit area large enough for your group is ever elusive. So for those times where you must use the flash, count to three, but shoot on two! That way people are already holding their fake picture smiles, but they aren't "prepared" for the flash and don't blink in anticipation of the flash hurting their eyes. A little bit of misdirection always helps get the shot!