Let 'em vent
Set aside time at your weekly team meeting for complaining. Take notes and follow up with solutions, and offer updates at later meetings. Your former peers, now your direct reports, will start to see you as a leader who follows through on promises.
Open your door, but not too wide
Invite your team members to stop and chat whenever they want or need to, but begin to put a little bit of space between you and them. That space is important because, one day, you may have to lay off or discipline some of them.
Don't wimp out
You're not -one of the gang" anymore, and you can't please everyone all of the time. Your former peers may test your mettle by forcing you to settle disputes. You can earn respect by demonstrating your willingness to make tough calls.
Protect and praise your people
One of the best things you can do for your team members is to act as a buffer between them and the company's executives. Praise your people in front of other managers. Stick your neck out for your team, and ask for more time when projects hit legitimate delays.
Encourage professional growth
Look for management training or mentoring programs to help your new reports enhance their skill sets and their opportunities for professional growth. If your company offers a mentoring program, use it. If it doesn't have a mentoring program, start one.
You can expect a few bumps along the way, but if you survive, you'll have a huge amount of management experience under your belt.
