These are some of the methods I personally have found help to facilitate a "distraction free zone":
1) Put my phone on airplane mode
2) Disable all app notifications on your phone
3) Log out of Facebook, Instagram, Snapchat, etc. (this one is admittedly so much easier said than done)
4) Use apps like Freedom that will turn off certain websites or internet
5) Set the mood: listen to music that gets you in the flow! I know that there are conflicting opinions on listening to music while working, but honestly I feel that for me working with the right music on in the background is part of why I did well in high school and college.
6) Minimize interruptions: prevent this from happening by informing people that you'll be occupied with work
7) Snacks: always keep some tea or coffee by your side, and most importantly WATER
In your quest for free productive time, remember that preparation is your secret weapon! Relax, take a breath, examine the situation. The reality is that uninterrupted work requires us to take preemptive measures against distraction. Taking concrete steps to ensure a distraction free environment is vital before you start tackling the to do list. Most distractions are external.