Disclaimer: These are tips which personally help me and are in no way medical advice, or proven strategies.
Put everything on DND
Phone, laptop, iPad, watch, whatever electronics you have, put them on DND. I find I will go to answer a text, then somehow end up spending an hour on my phone without even realizing it, and sometimes without even answering the message I originally went on my phone for. Do not disturb is actually a life saver for me. Sometimes I have to put my phone across the room, because even having it right next to me can be a distraction, and the only reason I use it while studying or doing homework is for music.
Use music but pick it wisely
When I have trouble focusing, I notice lofi music helps me concentrate so well. The music quites my brian, but it doesn’t distract me with lyrics. Even instrumental music for songs I know can distract me because I’ll try to fill in where the lyrics should be. Thunderstorm sounds also help keep me focused and my brian calm. Most people have probably heard this, but Mario Kart music is perfect for when you have to write a paper or do a reading because it makes your brain want to go quicker.
Highlight and write on readings
If able to, I always highlight and write little notes on my readings. It keeps me so much more engaged in the reading. Even if it’s not something necessarily important for the class, I will highlight what I find interesting. Most of my notes have nothing smart or important in them, it’s mostly a way for me to connect it to something in my life, and therefore helps me remember the material better. It also helps because I’m not just sitting still while reading, it actually gives me something to do.