1. Since group pictures are usually done immediately after the ceremony, please inform your family well in advance to stay put and not rush to cocktail hour. The more information they have about what to expect, the better. So maybe, a week before the wedding, it would be great if your immediate family would get a short, kind, and sweet reminder about the family formals, especially the location of where they will be done and the timing. Mention their importance and that you look forward to having them all there. Treat this moment of your day as a great opportunity to catch up with your family members that you don't get a chance to see too often. Once you get to the reception, the music will be too loud and there will be dancing to be done...
2. Designate a family representative for each side (bride's side and groom's side) to help with organizing. I always try to remember everyone's name and role, but it is almost impossible to get everyone right. Also, I have a soft voice and struggle with being loud and acting like the "family formal commander."
The family member you choose, ideally will be the organized, fun, and energetic family clown - that one person that has a knack for keeping everyone happy and in line all at the same time.
3. The LIST! Have a detailed list of each group you want to take pictures of and the order it should be done in. As a rule of thumb, it is way easier to subtract family members from a large group than doing it the other way around. (If you start with the small grouping, you will have a lot of sitting around for a bunch of guests. The other way around, you can dismiss people as they are done so that they can go enjoy the cocktail hour.)
4. If you have a group large than 15, make sure you have chairs handy, or a way to get them fast. Large groups need to be organized in layers with the shortest members in front and grandparents or seniors sitting. (not necessarily because of the age, but mostly as a sign of respect to them). I usually make sure I have at least 5 folding chairs in my trunk at all times for this reason... (sometimes, the ceremony chairs are used to set up the reception room so it's best to be prepared for anything and everything.)
5 Lighting. Everyone craves that creamy, natural light. No matter how skilled the photographer is, that is a very hard look to achieve in harsh sunlight. It is usually the reason we look for that patch of shade and try to keep the sun behind the group. Sure, flash and off camera lights are an option but they tend to look a little fake. It is also a matter of taste and if you do prefer that look, please make sure you let your photographer know ahead of time. If instead, you love that bright, creamy, natural light look, keep in mind that shade is needed. Sunlight is great for adding drama but not in family formals. I won't even mention the constant squinting... Oooops...I mentioned squinting...
6. If your ceremony is later in the day, make sure the sunset light is reserved for your couple portraits. So, if you work your way back from couple portraits during golden hour, you should easily figure out the ideal time for your ceremony and family formals. Allow about 1 hour for the group pictures (but this also depends on how large your family is and how many different groups you have)
I hope these tips were helpful. if you have any questions, do comment and ask or send me a sweet e-mail. :) I will be happy to help you figure things out.
Geesh --- I talk a lot, don't I ?!?!
Peace. Love. Family.