Execution is the ability to get things done. At the simplest level, it's knowing how to:

1. make lists
2. attend to mundane details
3. check and recheck for omitted items or people
4. follow plans through to completion

At a more sophisticated level, the ability to constructively and assertively manage the following to get things accomplished in social systems.

1. power
2. political relationships
3. symbols

via J. Richard Hackman