Ultra productive people don't work from a to-do list, but they do live and work from their calendar. Do you really think that the billionaires like Bill Gates and Marisa Mayer write a long to-do list and prioritize items? Nope, if it's not on their calendar it just doesn't exist because a to-do list doesn't account for time.
I read this crazy Forbes article about time productivity and started to put everything on my calendar in timed increments, like the billionaires. When I sit down to start the task I ask Siri to set the timer. 15 minutes of Instagram interaction, 20 minutes of Facebook group trolling, 30 minutes of email management, 60 minutes of content creation then a break.
Bottom line if it doesn't get scheduled and Siri doesn't time it, it shouldn't get done. It's a learning process for me but so far it's working out pretty well.