David Allen's threefold nature of work:

• Pre-defined work: Work you've set up ahead of time.
• Work as it appears: Work that interrupts you.
• Defining work: You sit down and think about what work you need to be doing.

• Effectiveness is goal orientation. It's picking something to do. This is doing the right things—picking a goal and doing that goal.
• Efficiency is doing things in an economical way, process-oriented.

• Change the way emails appear in your inbox: set up a folder for emails that you're Cc'd on and a folder for emails that come directly to you.
• Don't reply to emails in the morning (or at night): it teaches people that they should expect future replies from you at that ti...

If anything important happens in the world, it will come your way many times. 

There's no need to hit refresh every 5 minutes on news sites. Somebody will tell you. 

When you're multitasking you are actually doing something called task-switching, which requires context switching. And this harms your productivity overall.

• Do It
• Drop it
• Delegate it
• Defer it

Only do it if it's going to take a minute and it's been scheduled. Otherwise, just drop it, delegate it and defer it.