Attire

I encourage you to take a little time and think this one through beforehand.  The outfit you wear can easily enhance or take away from the overall look of your photos.  Personally, I feel solid colors really add a lot to a great photo, as well as layering.  Patterns are good, but definitely when kept in moderation.  Having multiple patterns can add texture, and when done correctly, will look fun & fabulous; but this tends to be tricky to pull-off.  I try to steer people away from wearing something with a large logo or easy-to-read words, because that will be the first thing someone's eyes are drawn to when looking at your picture.  Also, avoid neon or "hot" colors.  They can create color casts on your skin which aren't pretty.  For family shoots I recommend not getting all "matchy-matchy" by dressing everyone completely alike.  That style was really popular for a while, but has now changed.  Pick a few complimentary colors and stick with those.  Hats (not so much ball caps), scarves, headbands, chunky bracelets, and other accessories can really add a unique and fun look, so feel free to bring some along to try.
For maternity sessions, I recommend avoiding stripes or clothing that doesn't accentuate your adorable belly.  Long "flowy" dresses are appropriate.  Ladies--especially senior girls, be sure to wear a little extra eye makeup than you typically do.  Better yet, hire a professional to take care of it for you.  It's amazing how much more that can make your photos stand out.  If you have any additional questions, don't hesitate to ask.  I'm willing to go through your closets with you or even on a fun shopping spree to help however I can!