A wandering mind is my biggest distraction. I don't have a problem with notifications, every notification I have is shut off. I can listen to music to prevent distractions. I can also close my office door which lets me know its time to create.
I'm best at about 2PM. I shut the door and work for 45 minutes then reward myself with 15 minutes of hobby, reading, checking social media, then back to work. A timer works very well for me.