How to motivate highschooler to put more time in studies ?

Re: How to motivate highschooler to put more time in studies ?

He knows he cannot. About the grades of his friends , I will not know , they come over , they are well behaved and well mannered kids when they come to my home to hang around.
After my intervention he is even getting extra credits in his tests so it is working , but I want it to become automatic , but I guess that will not happen I will have to be on top of it.