This is the first lesson I learned when I become a Manager of a development. 'Treat your Developers as Responsible Adults and Trust Them'. This simple advice, gave a me big advantage Trust and Support of the Development Team. It starts with a simple ideas. Let me give an example to clarify my point.
Scenerio : An Important release of your project/product is coming up and a developer comes to you and asks for a 2 day vacation (leave). What will you do ?
The most common reaction in companies/project groups is to DENY the request. Manager will ask the developer to postpone it or even go to extremes like accusing him of 'not being a team player'.
Saying 'no' is a REALLY BAD IDEA. Does your team know the importance of the release ? Do you trust the judgement of the team members ? Do you treat them as kids to be disciplined or as responsible adults ? If you are treatng them as responsible adults and if the developer knows the importance of release and still asking for vacation, then it must be that important for him. So Don't be a PHB AND say that 'YES, you can take the vacation'.
If my release is stopped because of unavailability of one developer, then actually I am a BAD MANAGER. In Software, people do change companies. So if only one guy knows some part of the project and if he leaves for some reason, I (the Manager) am in major trouble. Its my responsibility to ensure that doesnot happen. I should not pass the blame to the team.
Treating developers as 'responsible adults' has lot of side benefits. You become part of THE TEAM. Lot of times, its team versus Manager (you). Now its Team (you + developers+qa) versus the product/project/deadline/problem. Now you have much better chance of Winning.
You respect the team members for their abilities and they respect you for your abilities. The Team is much more confident to suggest unconventional and innovative solutions to problems at hand.
If I ask the team members to come on weekend (a rare ocurrance in my teams), the team comes in without any complaints. Most of the time I don't even have to ask. If they feel its neccessary work on weekend for some reason, they will come on their own.
The team depends on each other expertise, advice is freely sought and given, the team morale and hence productivity is high.
Its real WIN/WIN for everyone...