I heard from a certain talmid chacham that a person should think the following three thoughts [and he will surely devote himself to Torah study]:
(1) One should think that he has only one more day to live.
(2) He only has this one page of Gemara (or just this chapter of Mishnayos) to study.
(3) He is the only person in the world whom Hakadosh Baruch Hu commanded to study Torah, and the existence of the entire world is dependent solely on him.
~ The Chofetz Chaim (Ahavas Chessed 2:11)