Do a schedule that you MUST follow. So that way there are some times on a day that you will just study. Be strict on that schedule and make it match your abilities. Don't make it so that you will break the schedule (you must know how much at a time you CAN study/read). Like from 9-11 am strict study and from 4-6 pm strict study. For example. Other time is your free time and you can do what ever you like. It is HUUUUGE benefit if you can study elsewhere than your own room/flat. Library or something like that will do (cellphone and all communication should be disconnected

). That way your scheduled working time will be physically separated from your spare time.
And when you keep on that schedule every day it will be easier to stick with it every day (like example every day reading hours from 9 am to 11 am). It doesn't make things easier if the study hours are different every day.
I had 170% of the required studies in amount when I graduated. (Don't ask why. I'm just interested in lots of things.) That was possible only with that strict study hours that I made for myself.
I actually am lazy as hell and I think I have some sort of ADHD because I can not concentrate to things for that long at a time. I can watch youtube videos for hours but studying is hard. So I made my study hours one hour long per day at a first. When I had one hour of study every day it was clear and that was time I could concentrate. It is still better to make that schedule for your study/reading hours for ONE full concentrated hour a day than do randomly few minutes at a time. And that "other-place-than-home" is the best place to concentrate.

No computers, no TV, no distracting friends.
AND if you really do a schedule you can feel actually more free. That way you don't have to stress about the studies ALL THE TIME because you know you have your schedule and because you have made that schedule for your abilities you can safely say that you are doing everything you can. If it doesn't get you good grades you just have to think "could I schedule more than 60 minutes a day for my studies".
It is actually funny that one must study your own way to study, to study.