I don't really manage it. I just let it flow, I don't feel guilty. That's the first step.
I also disable browser & desktop notifications. It's fine to see a highlighted tab or a number in the systray.
My mobile is always on vibration. Social apps are muted. All of them. I wear a Fitbit wristband synced by Bluetooth for phone calls notifications.
I use Serializer as main input of news. I check it between tasks, scanning the titles and sending the articles to Pocket (important!).
I let myself check anything at any moment. When I feel "the urge" I just ask myself "should I check something?". Take a few seconds to answer that and I usually keep going on my task and check later. If not, it just happened. No big worry.
I also keep myself away from Twitter & Facebook using Buffer to plan my publications. I use Goofy or Pidgin to connect to Facebook chat.
Finally, I use Evernote with a keyboard shortcut to open my "brain dump" note. Here I jot down quick ideas that come across my mind while I'm doing a task. You can use anything else but Evernote is useful even walking. You can write down in your mobile and sync it later at home/office.