Each child is different and motivates differently, some maintain their attention quite easily while there are some that do not. Some children may be strapped with actual behavior challenges.
If the behavior becomes disruptive enough and constant enough that typical behavioral management techniques fail to produce change, it could be time to seek additional resources and testing for your child. This is generally true when managing the child's behavior becomes the focus of the day and actual learning is taking a back seat. This can be an additional burden if the disruptive child begins to affect your other children if you are indeed engaged homeschooling more than one of your kids at a time.
If indeed a learning disability such as Attention Deficit Disorder or Attention Deficit Hyperactive Disorder is determined then preventative measures can begin early on in your behavior management strategy.
With many children perceived behavior problems can actually stem from a lack of success in whatever tasks you may have them attempting to learn. In other words the child initially struggles to learn what is presented or cannot perform the task well enough to perceive success and this results in the child not wanting to do the task or stay focused on the learning event because they feel they have little chance of success. Frustration builds, and so does the "attitude". Success begets success and motivation will run higher making your behavior management a much smaller part of your day if you do your best to ensure successes with your child's tasks then celebrate each of those accomplishments. As the successes rise behavior and discipline issues will decline.
No one set of rules applies to all children. But barring the diagnosis of any of the more serious learning issues, reaching lofty goals and achieving high standards is accomplished by one small success at a time.
