Dressing your family for portraits requires some coordinated effort.  The focus of the portrait should be faces, not clothing, so plan with this idea in mind.  If you're planning to display your portrait as a focal piece in your home, you also will want to consider clothing selections that will complement your home decor.

Select a couple of neutral base colors, something that most everyone already has in their closet - blue jeans, khakis, white, gray, tan, black. Choose  2-3  colors to mix and match within the group.  Each color needs to be used on several people in the group.  Use layers and accessories.  Solids tend to work better than multiple patterns and prints.  Lay out all of the clothing together in advance of photo day to see how all of the pieces look together, paying special attention to whether any piece demands  more  of the attention.   I'll gladly work with  you to create coordinated combinations that will have your family looking their best on portrait day.