I am currently studying “Get Altitude” and one of the key lessons that Eban emphasized was:

1) STOP Multi-tasking 

I could not agree more.  This is a disease!  For whatever reason people are obsessed with multi-tasking (think email, IM, Skype, Twitter, etc.) and accept constant interruption. Being a great multi-tasker is not something to be proud of! 

You must be able to get into FLOW at which point your productivity and also creativity and enjoyment of what you are doing reach a max.  Getting into FLOW while multi-tasking is impossible.  So, always try to chunk your time.  Spend 1-2 hours on a task, then take a break but whatever you do, try to stop multi-tasking. 

It’s always good to take a step back once in a while and be reminded of what is important.  Eban also stresses the importance of having intense experiences both at and outside of work.  If you don’t, then you just get tired and burn yourself out.