When you have lots of thing to do, plus many potential distractions in your ‘line of sight’, even if you are disciplined, and have chose just ONE thing to do right now, there’s a good chance that at some point during the duration of that task or project, you’re going to encounter an interruption; an obstacle to your ability to remain singularly focused on the task at hand.
Even if you have set up your environment to minimize this, which I recommend, it’s still going to happen.
So, while there is a long list of things you can do to help yourself, on top of that, or perhaps even before you do all of that, there’s one additional thing that Nir didn’t mention:
Surrender.
You must surrender to the reality that no matter how ‘Indistractible’ you are, distractions will occur.
Thus, when they do, the choice will be up to you how to respond.
With grace, or frustration?