Being photogenic is not about looking beautiful or wearing expensive clothes. It is natural for some people and often comes from innate self-awareness. However, it is also a skill, much like acting, that you can improve with practice.
My goal as a photographer is to convey the essence of my subject’s being. At times this means creating an elegant , formal portrait, and other times it means conveying simplicity and everyday reality.
Children are natural wonders, and a skilled photographer knows how to capture their essence without being intrusive. When photographing your children, please don't bribe, push, criticize, or tell them to say "cheese." Don't force them to pose. Wait for another opportunity when they are feeling cooperative. Sometimes a child prefers to be photographed with a person they trust. To get them interested, show them the digital image in the camera's display window. If a child is treated with patience, respect, and understanding, then they are more likely to work with the photographer, which results in better pictures.
Some other points to keep in mind for your photo session
Simplicity is the key. Avoid logos, large or bold patterns, and bright colors because they draw attention away from the face.
Avoid sport shoes and T-shirts. Bare feet are nice in casual settings.
Dress everyone in the same style of clothing. Do not mix casual and formal.
Solid colors are best. Keep the tonal range of clothing the same within the group. Don't mix light and dark colors.