We all remember from English class the rule of Subject -- Verb Agreement, which means you wouldn't say "That book are great?" but rather "That book is great." The same rule can be applied to photography, if we look at how the subject of the photo relates to the framing of the picture, what I call Subject -- Frame Agreement. The most common incident where we find this error is in distance. Being too far away from the subject ...
Group shots can be hard to organize and pose. The key is to go in with a plan. You may do one photo that is more traditional (tall in back, shorter in front...lined up shoulder to shoulder), but then have a more casual photo where people can sit down and turn toward each other. That way you have a photo that should please everyone.
