some ideas:

1. Be yourself. Your co-workers already know you, so don't try to be something different. You can still go to lunch etc. Just be careful not to talk about the 'confidential' info you may know that is not public knowledge yet.

2. Lead, don't manage.

3. Give frequent feedback. If you see someone doing something right, say so and thank them. If you see someone doing something wrong, privately talk to them about how they should have done it. Read "The One Minute Manager" for more about this.

4. Resist at all costs the urge to micro-manage. It is amazing what giving a person a job to do and then leaving them alone to do it will accomplish.

Good luck.