There's a line in the Bible that goes like this:
when I became a man, I put away childish things.
Becoming a man isn't an event but it often begins with one.
A first kiss, a first beer, a first fight.
Similarly becoming a productive person isn't the result of a one off. It's a process that gets repeated until it becomes second nature. Pretty soon you get a reputation for being the type of person that gets shit done. Building this rep should be your number one goal in work. If you succeed it will follow you about like a fart in a phone-box.
So how do you start the process of becoming a productive rockstar in work?
Start tomorrow morning by making your intentions clear:
Put away everything that isn't related to the task in hand. Then bring into full view everything that is.
It's as simple as that.
Close your email if it's not related to the task. Put your phone in your drawer or on airplane mode. Put your headphones on if it helps block out distractions.
Likewise put everything that helps you focus on your to-do list in sight. Make your to-do list the star of the show. It should be the sole focus of your attention for however long it takes you to complete the task you're attempting. Keep it at eye level. If someone lands at your desk point to it. Tell them you're not available until you've complete task XYZ.
Then keep at it until you can strike the task off your list. Become a man (or women), put away unproductive things and build that reputation. Also, behave yourself at the xmas party.