For sure shooting kids is not an easy task even for master photographers. As a rule children are not eager to listen to your instructions about posing as carefully as adults do. So, they will not follow all your recommendations exactly. Moreover, often they have their own image about future photos.
Be ready that sometimes they will stand their ground about choosing location, cloth and, that is the most important, poses. The photographer usually faces a challenge how to make an amazing and in the same time rather natural pose. In addition to this, you will have to think about the atmosphere of the future photoshoot.
Your main task is not to make a child follow all instructions, but to get the idea and emotions of the photos you want to have finally. Remember, that every child`s smile, every little gesture should be kept.