Encourage your student to remove all distractions while they are completing their homework / studies. Distractions include cellphones, television, social media, video games, noisy areas and friends so they can focus on their studies and complete their work successfully.
Routines are important. Set up a time that works for your student and yourself. Find a quiet area where they will work without distractions. Set it up for the same time everyday and the same duration. If they have no homework ensure they use their time to review their notes, rewrite notes, work on projects or study for a test.
Create an agenda with them to teach them to be accountable. Ask them to write down their assignments and tests as well as record their after school studies every day. This will give a clear picture of what they are doing during their after school study session.