I think the key to avoid interruptions by planning your day. You can try to write hubs while the child is napping, for example, wake up early or stay up late so you can write while the family is sleeping. You can go out to a library or coffee shop to do your writing, or designate a particular time to write and close the door and insist that no one interrupt you during that time.
This is not always possible, so I try to structure my day so that I am reading hubs, answering questions, responding to comments during the time when I am expecting to be interrupted. Then when I think things are likely to be more quiet, then I research and write hubs. I always try to write down my ideas and keep track of where I left off, so that when I do get an interruption, I can come back and resume where I left off.