This past weekend, I photographed a sweet family of five.  When I was talking to the wife and mother of three about preparations (location, time, etc.) she also asked me what I suggested she and her family wear for their portraits.  I told her right off the bat to try to avoid logos, black and white or too-bright, conflicting colors, and not to be all matchy-matchy (they didn't need to all wear the same exact shirt, for example) but past that, I was stuck on what to suggest.
I did a little research (thank you, 
Pinterest!) and found some excellent recommendations for couples and families who are preparing to have their pictures taken.  For my own purposes, I want families and couples to feel relaxed and comfortable, and this can be strongly linked to what they're wearing -- if you're dressed up too much, you might feel stiff and awkward, and trust me, that will show in your photos!  I think it's better to convey your true selves for optimal photographs (though you should probably generally avoid sweatpants and running shoes).
A great piece of advice from photographer 
Lexia Frank: "The biggest myth I can bust here is that 
you do not need to match.  
Actually, please, don't.  It is so fake and contrived, and as a 
photojournalistic photographer I’m doing my best to keep it real -- I just
 can't with matching outfits.  Coordinate, sure, but don’t match."
Here are some examples of what I love (and maybe a few examples of what I don't).

This first example looks good to me because it covers a couple of bases: it's not too matchy-matchy (the grouping of muted primary colors is coordinated without looking too contrived), it's casual and relaxed, and it looks like a natural setting.  This image shows the family in a context that could happen anywhere, anytime -- this photo could have even been snapped in front of their own home.  They look like they simply paused in their conversation to grin at the camera, and then continued on their morning walk.  I love that.
{image by 
Ashlee Raubach Photography} 
I'm also a big fan of images that are candid and editorial.  I really love images in which maybe just a couple of people are looking at the camera, or no one is looking at the camera!  I think the photo below is a good example of this.
I like this portrait because, as I mentioned, no one is looking at the camera.  Mom and dad are posing, of course, but it's certainly not so formal or traditional.  I don't love it that it looks like the two older kids are about to fight, but I digress.  You get what I mean about candid, right?  Okay, moving on.
Here are a couple more examples of families unafraid of a little wardrobe diversity.  This next image actually has what I might characterize as TOO many patterns and it's almost distracting, but it kinda works.  What do you think -- too much or just right?
More pattern and color-mixing action that WORKS!  
I've also found quite a few outfit combination boards that mirror these types of ensembles: coordinated and cohesive without wearing identical outfits.  Here are some of my favorites:
 
 
 
 
Some additional tips for dressing for portraits, borrowed from various sources (check out my 
Portraiture board on Pinterest for more!):
- Do stay in the same style group together.  If you’re going formal, you all need to be formal and likewise for casual.
- Dress for the weather.  There is no sense in having a well-planned 
outfit but having the children freezing (or sweating) and unhappy during the shoot.  
It will show through in the photographs.  Have backup outfits ready for cold weather.
- Textures, patterns, and layers give interest to your 
shoot just as those same elements give interest in interior design.
- De-stress beforehand, even if that means having a glass of wine. The
 kids can read your level of stress and will act accordingly.
- Flowy dresses are always a big bonus; anything that shows movement will translate beautifully to photography.
- Consider getting your hair and makeup professionally done; it makes such a huge 
difference in how you feel during the shoot and the final product 
afterward.
- Have snacks for the kids ready, and make sure they get a good nap in.  That goes for you too -- remember, they can read your stress.
- Trust your photographer.  
Remember, it’s all about the light, the connection between you all,
 and the location.  A boring parking lot can be completely 
transformed once you step into the best light.
- Give your photographer some space when she photographs the little ones.  Hovering 
parents does not help, no matter how much 
you want it to.  The very best images are not when 
they are smiling at the camera.
- Only bring props that you feel are intrinsic to you as a family and that are interactive.  The main objective is to photograph the love and 
connections in your family, not the items in your life – unless they 
relate directly to your love.
- Don’t put off shopping until the last minute and wear your clothes 
for the first time on your shoot.  You want to know what you can and can
 not do in them.  If you feel restricted, it might not be the best 
choice 
- Your shoes will be shown in photos, so don’t forget about that style!
- Sometimes less is more, but that doesn’t necessarily apply to 
clothing! The less skin exposed the more we focus on your faces and the 
connection between you all, and the more timeless your photos will be.
- Don't be late.  When that 
sun sets, it’s all over. 
Do you have any good tips or suggestions for great family photos?  Share ideas or links below in comments!