When you work together, it's easy to become friends. When you become the manager, those relationships change—which can be uncomfortable for both you and them. Here are some keys to success:
Be open about your feelings regarding the role. You need your friends' support and their suggestions about being a better manager. Review your expectations and how you plan to be effective at producing results and treating everyone equally, while still maintaining your friendships.
Set clear performance standards. Your job is to create a system and an atmosphere that help each of your friends on the team to be more effective. It's not to cover for them or let them do sloppy work. Help your friends identify the goals they want to achieve to succeed at their work, and then use these to develop agreed-upon performance standards.Don't grant favors to your friends. Just don't. It's an easy trap to fall into, but it creates nothing but problems. Everybody ends up paying the price if you let some people get sloppy, or if you demotivate newer team members because you're paying more attention to your friends.
Make new friends. You will need to put some energy into developing relationships with all your team members. Not only does this help avert feelings of favoritism, but it also allows you to get better results from supportive relationships with everyone.