McKinsey recommends.
1. Don't multi-task. Experiments have shown that it takes 30% more time and doubles the error rate.
2. Constant exposure to new information inhibits creativity.
3. Self-control: focus, filter information, take appropriate breaks.
Find your "alone time".
Don't reply to cc's.
Phone calls are better than emails.
7. Give up the illusion that you have to do everything yourself.