Documentation of work !
The reason why most projects are so poorly managed is that what needs to be done is never clearly documented.
A lot of what people work on is decided on an ad hoc basis and is often determined by off-the-cuff conversations managers have with each other based on their personal priorities.
Most of these are never formally recorded, as a result of which work just piles up typically on the programmer's desk, who is then labelled as being the bottleneck because he is seen to be inefficient!
The trick is never to do anything unless it is formally documented! This is why it's equally important to record what you are not going to do as clearly as you record what you are going to do!
Everyone should be aware of these decisions so that no one can sneak in their personal priorities informally!