This is just a timely piece.. And all you experience are my experiences too. It sometimes takes a lot to get my mind to focus on one task, especially when I have many brain tasks to perform..

Sometimes what I do is play a calm music and start singing along, then I can finish what's at hand in no time. If it's about writing, I just shut my eyes and meditate on what's distracting me, figure it out in my mind, then my head gets cleared for what I need to write about..

I'll practice the other suggestions you listed.