Chewing gum can help you focus on studying. Also, you should go into a quiet room where there won't be any distractions. For me, I like to also play music that doesn't have words quietly in the background. Lastly, you could make a studying game. For example, every time you study a question you can test yourself on it in like five minutes. If you get it right you can eat a piece of candy or something.
I hope this helps!
