If you teach for any length of time, you will eventually have a student (or two) that is easily distracted. See if these scenarios sound familiar. Another student gets up to get a tissue, the "D" (distractible) student watches in complete fascination. A squirrel runs by on the tree limb near your classroom's window, your "D" student quits working to watch what the squirrel is going to do next. Anything and everything seems to be more interesting than doing what he or she is supposed to be doing. It doesn't matter if this student is supposed to be listening to the story you are reading to your class at circle time or a paper-pencil assignment, this student is distracted by the world around him or her.
By this time of year, you have probably tried many different strategies. I have a few things you might want to add to your bag of tricks to try with your student(s).