marshmallow i agree with what some have said; listening to music (on a single playlist to avoid distraction), etc. begin with a to-do list and make it your goal to get through that to-do list before the end of the study session or day. i also time block these tasks into google calendar, which enforces how long to spend on each task. finish early? do another task or take a bigger break!
if you struggle with distractions, use ypt- locks apps on your phone and you can choose what apps to allow.
hope these help!