How can I stay focused on studying without getting distracted?

Make sure all little jobs are done.
You've eaten, so no rumbling tummy.
With a glass of water and all books needed, go to a quiet calm room.

Studying in a silent room without any technical devices makes me more concentrated to my work. And, a darker room than the usual really puts me in the mood for studying or reading somehow weirdly. Maybe i’m more productive in the night time.