I learned this "technique" a while back and it's so simple, it seems stupid. However, it works wonders for some of us.
Open a session of Notepad (or other simple text editor) and in HUGE point font type in your immediate responsibility.
Keep the document open, and if you are prone to not "full screen" the applications you work with, make sure that a small portion of the document is always visible. If/when you get distracted, click over to the document and read the short statement reminding you of what your current task is.
Yes, this sounds silly, but for some of us, seeing something helps jar our minds to focus on what we need to focus on. Eventually, your mind will be trained to just see the corner of Notepad and think "Oh, yeah let me get back to that."
It's just a way to re-condition your mind to stay focused on your work.
Now I have to go. Notepad is telling me to create a few, new user accounts...