One way to encourage the good habit would be to set aside specified study time every week. A schedule can help develop a mind set for studying during certain times. It is much easier to read difficult material if you have your mind focused on the reading. Finding good places to study can be just as important as finding good times to study. The best places are comfortable areas where you will not be bothered.
Some students also find it very helpful if they see other students studying as well.
Sitting in the library and observing many other students working diligently on their assignments tends to have a distinct motivational effect on all but a very few. Some others prefer a more open air environment and do their best work on the various campus lawns. But the most important factor is to find a place where you can limit distractions and concentrate on what you are studying. Divide the assignment into parts. Simply looking over the problem set may give you an idea of how much time you will need to spend on it, but this amount of time and effort may not seem very appealing.