Okay, For individual portraits just keep in mind the rule of thirds so if the person is facing left keep their head on the right of the frame etc. I don’t have very much experience with groups but something I’ve found that helps keep it organized looking is to create diagonal lines with peoples heads and also triangles if that makes sense. 🙂 Try not to have just a straight line of faces, so like have some people standing, some sitting, and so on.
Hope that helps!
This is just some things I have learned through lots of trial and error 🙂