Tips for parents to keep students on task.

Divide larger tasks into small component, breaking after the task is finished. Enjoy rewards together, once the task is complete or major milestones achieved.

Pay attention to diet as well, avoid sugar & caffeine & other foods that spike blood sugar & lead to crashes. 

teachhi or her balance by examples reading separating from electronics  etc

Something like RescueTime might be useful, also set a schedule and reminder to take breaks etc

Best one I've ever found is have them do the work and then come out and explain it to you. Keeps BOTH of you involved in their progress and virtually eliminates prevarication.

Have an activity tracker installed to be able to see what your children have done. This way you will know if they are doing their homework or just doing other stuff.

Turn OFF the WIFI in your house when your child is working on something that can be done on the stand alone computer.  That will at least eliminate that distraction; as no messages to send or receive, and no surfing can be done.   Perhaps  offer a small Incentive for when they complete the task; along with congratulating them for being so focused..  And telling them that being able to stay on task is such an important skill.  (Also take away their phone for that time, IF they have one.)

For  my students, sometimes "chunking" similar types of work together makes it easier for students to stay on task.  This way, large assignments are broken down to smaller steps.

That's actually a really good question. I'm interest in seeing the replies

If it's book reports, disable the internet if you have that capability. He doesn't need internet to write a paper on a book. Best suggestion I have though is to have him work in an area of the house where you can easily monitor what he's doing. He doesn't need a computer in his room.

Be active in their days, and yes I know easier said then done.