After you've chosen your color palette, choose one or two bright accent colors that you can use for accessories throughout the photos. If you've chosen a toddler girl to take center stage in the photo, look at the colors that are in her outfit. Her outfit might feature a pattern with gray, teal, and salmon colors. Mom can wear a bold teal necklace and matching earrings, Dad can sport a salmon tie, and the big brother can wear a funky bowtie or some fun teal socks. The possibilities are limitless.
Consider using multiple accessories for each subject throughout your photo shoot. Depending on how many accessories you have, you can do one or two changes throughout the shoot. This is much easier than doing full clothing changes, but it's enough to give photos a whole new feel.
Rather than making accessories a static part of the photo, get subjects interacting with them! Baby can grab Mom's necklace during a photo, a child can hold their hat in front of them for a picturew with a little bit of attitude, or you can have someone drape their jacket over their shoulder as they turn towards the camera.
Look into parents' wardrobes for accessories that kids can use. This plays on the jubilance of youth and creates a link in the photo between a parent and the child. A little boy looks adorable with his dad's hat balanced on his head, and little girls often love playing with mom's jewelry.