Try to focus on some of the good things that will come from studying. Imagine how you will feel when you are prepared and confident at the time of your exam or assignment or whatever you're studying for. Then schedule several shorter study periods so you don't get overly tired cramming at one time.
One strategy called the Pomodoro method involves using a timer and studying or writing for around 50 minutes and then taking a 10-minute break, and repeating that for 2-3 cycles.
Try to set some short goals and build in a reward for yourself at the end of those study periods.
Finally, know what works best for you. For some people, flash cards are useful; for others, Witten or video journaling on what you've been studying is helpful. So reflect on what has worked well for you in the past and build on those strategies-even if it's only worked well one or a couple of times in the past!
Build on your strengths, aim for short but repeated study sessions, and reward yourself for sticking to your plan!