[glancast]

I've found FocusAtWill invaluable -- it's music designed specifically to keep you in flow. I use the timed function to ensure I take breaks at proper intervals, and you rate how focused you were during the session. http://ssqt.co/mQbYXSq (this link gives you $20 bucks off your first bill if you decide to sign up after the trial)

paper: https://arxiv.org/abs/1610.04255

"how it works" (with citations): https://www.focusatwill.com/app/pages/science-of-focus-conce...