they will not be self conscious and more likely be natural in their expressions and you are familiar with the layout of
the house meaning the best location and lighting.While outdoors or at venues like church or wedding reception with many
people it may be daunting so must have a plan on how you will execute your assignment.Going through mentally will
prepare you some what.Your camera and lens cover most of the focal lengths used for intimate as well as group portraiture.Hope you have an external flash as group photos require more light in large venue as built in flash is only good up to 35mm and short distance.Of course direct flash will cast hard shadows so an external flash that have swivel head
and with the addition of diffuser will lessen such hard shadows.Are you familiar with existing light photography? It gives another dimension to the mood,make use of light from windows to give additional lighting.
You are already familiar with your camera controls.Go through the check list of what you should bring along like spare set of battery and memory card.Blower brush etc.As you are not the main photographer no point to use tripod.Most likely you will be moving from places and viewing angles.Anticipate photo opportunities.You have autofocus,exposure and large memory so it's a matter of pressing the shutter button.Have situational awareness,many scenes/photo opportunities are
are taking place.Go through wedding photography books for examples and inspiration.Post your work in the photo gallery
section for us to enjoy.Good luck you can do this.