do it in increments. set a timer for 15 minutes, study, then take a 5-7 minute break and go dance, draw, sing, write etc. and then repeat the process. yes, it takes longer but it helps.
i find it helpful to play music. nothing that i know i'm gonna want to dance/sing to, but more instrumental music or "study playlists" on youtube. whenever i start to feel too stressed, i take a break to stretch, sing a song that helps me destress (twice is my favorite for this), or have a snack. also, if you're frustrated, complain! i often take breaks to go complain to my mom about the material, the teacher, the class overall, the assignment, etc. it helps you to get out your frustrations out and clear your head. if your head is clear, you can focus more. also, i have adhd, so breaks are very important; so, if you feel like you need a break, then take one! don't procrastinate, but don't be afraid to pause, either.
I don't necessarily study a lot, but if i do or if im working on school work, I usually need something to play around with (pencil for example) and play music. Usually I choose songs that I get hyped up to, it works for me but it may not work for others, while studying.
I usually study at night which is an easy time for me because there isn't much noise and any other disturbances. I study one subject for about 30 minutes and take a 10 minutes break and continue studying another subject likewise. Like this I can study more than 3 hours continuously with having breaks in between. I don't listen to music when I'm studying because then I start to forget things, instead if I remember lyrics of a song while I'm studying, I write that particular lyrics on my notebook (actually when I do that, I gradually start to forget the lyrics and focus on studying) and continue studying. I have a white board and I study like I'm teaching my plushies. That's the most effective method for me to study and it helps me to remember a lot of things. If I'm exhausted from studying, I go to read a few chapters from a manga, or draw something.
Hope my method helps somebody! ^^