Ever since reading "The 7 Habits" by Stephen Covey fresh out of college, my overall time management framework has been approaching work/task with the four-quadrant decision matrix:
TLDR: By doing 2, 1 will go away or at least reduced dramatically. Be ruthless (primarily to myself) about saying NO to 3 and 4.
In terms of day-to-day time management, I use a variant of Pomodoro Technique (I did not even know this had a name). I have my computer tell me time every 30 minutes, and during one "unit" of 30 minutes, I absolutely focus on the work on hand. No sneaking at an incoming msg, no answering a call, not even a bathroom break.
The URL to wiki above as well as a number of sites have more detailed and formal approach to this. For me, I call it a good day if I can achieve about a dozen a day.
My job is programming, and I have practiced this for a while now, so a dozen comes pretty easy most of the days, and many days I go well over a dozen. The challenge is to maintain a streak even through the days that are not so conducive to focused work. Here, again, being ruthless about saying no to distractions is required.
By the way, note that my aim is about a dozen units a day, so about 6 hours. So this would leave plenty of time for meetings,1-on-1s, socialize, personal stuff, rest, etc. Just not during my focused maker time.