I'm more of a lifestyle photographer, I love natural photography and I want to capture the real you. I want you to be comfortable and to be yourself, so stressing about clothes should be the least of your worries. To put it briefly, you can wear whatever you want, whatever you normally wear, or whatever you would like to be photographed in. My photography sessions tend to be active and outdoors, so the clothes you wear should be comfortable .
This being said there a few clothing choices that I wouldn't recommend.
I advise to stay clear of Logos, big logos especially, clothing with writing across it or big pictures can distract from the most important subjects, which is you and your family!
Crazy patterns, zigzags and stripes that are very close together can distract too, and often they don't look good in print.
Neons. This goes without saying :-)
Fake tan and too much make up, the lens is powerful ;-)
Clothes that don't suit the time of year, if its winter, wear warm clothes, you may look great in those summer clothes before you leave the house, but the photographs will show how freezing you are at the session! Wooly hats, warm coats and comfy shoes photograph great! :-)
You all don't have to match ;-)
Personally I love neutral colours, I love autumnal tones, deep reds, dark blues, auburn, browns, greys, greens and yellows. I love wool and denim and I love flannel shirts! I loooove florals. I love long flowy dresses and hair down blowing in the wind. I love creams!
Its all a personal preference though, because I want to photograph and capture you and your family as who you are x