According to Cisco executives Ron Ricci and Carl Wiese in their book The Collaboration Imperative: Executive Strategies for Unlocking Your Organization’s True Potential, collaborative leaders exhibit these four traits:

1. Focus on authentic leadership and eschew passive aggressiveness.

Follow through; do what you promise.
Don't take things personally.
Communicate what drives your decision-making.

2. Relentlessly pursue transparent decision making.

Tell people clearly how you make decisions. And navigate tricky situations.
Be "open and transparent about: who made the decision, who is accountable for the outcomes of the decision, and is that accountability real."
"document the key decision paths of your organization and communicate them to your team as often as you can."
"Share your biases and tell war stories of how your successes and failures shaped these [decision making] biases."

3. View resources as instruments of action, not as possessions.

Share resources; not stockpile them.
Having a "common approach to assess and communicate resource decisions" creates a transparent environment conducive to resource sharing towards a shared goal.

4. Codify the relationship between decision rights, accountability and rewards.

Modelling: Show that you walk your walk.
Establish clear parameters: who gets to make decisions? Are all decisions tied to funding?

More here.