My classes require reading lots of book chapters. How do you keep your focus? I always drift off as I'm reading. It takes really long time for me to read. Only if I could sustain my focus throughout all the readings no matter how much it takes.
I always found it easier to stay focused if I do my reading anywhere other than home (too many distractions there), so school library, park. If it has to be home, a sugary beverage and bright lights do the trick for me.
Read, when you start drifting, put down the book, look at things far away, and get a little exercise. After a few minutes, you should be able to settle down for some more reading.