it is all about colours
Classic and timeless is the neutral colour palette. These look great on most people. They are excellent for summertime and beach sessions.
Autumn colours are fabulous all year round. A mustard yellow or burnt orange vintage style clothing can transport an image to nostalgic wonder. Greys and teals contrasted together give a modern pop of colour.
Red, navy, burgundy and deep purples are great colours for Autumn or Winter sessions.
Bright colours are always beautiful and sunny. Perfect for kids. Just avoid neon colours.
let's talk denim
I love denim jeans. If I am not wearing my pjs I am in my jeans. They are great for sessions too. My only advice is to not pair a dark top with light jeans. In fact with light jeans I would only recommend colours from the neutral colour palette. Dark jeans go with just about everything. Denim overalls look especially gorgeous on kids.
patterns & t-shirts
If you want to wear a pattern go for it. If you want to put a t-shirt on go plain, not a slogan tee.
wear what makes you comfy
I would rather eat a hat than wear a dress and I know it would show in my photos. Wear what makes you feel confident and comfy or it will show!
Keep to the same colour palette but don't match everyone in the exact some thing (like red top and dark denim bottoms). If everyone is in a neutral colour except for Mason in a red tee he will be the one to stand out. However, there are some exceptions! Maybe Mason is in a red tee, mum has a light summer dress with a red necklace, dad has a light shirt and beige jeans and little sally has a light beige dress with red shoes and belt that can work too. Just see what works for you and in you need ideas pop 'what to wear family photos' in Pinterest and you will get a lot of ideas.
if it's just the kids
This is the time to put them in what you love.
create your own style!