Set boundaries as a single parent and make sure your teens follow the rules.
Keep in close contact with your teen because you will want to know where they are at all times.
Have an open line of communication with your teens.
Reward them for good behavior without going overboard.
Treat your teen like they deserve to be treated. Ex: Treat them like an adult if they act mature. Treat them like a child if they choose to act like one.
Do make them tell you where they are going.
Act like a role model to your teens because they need that in their lives.
Talk to your teens about sex, drugs and alcohol. Educating them proactively is the key rather than assuming they will do well to know it on their own.
Prepare for their future in as many ways as you can. More preparation now means less scrambling around later.
Talk to them about their father and be open to letting them choose the relationship with their biological dad. Of course, you need to set boundaries, especially if drugs or alcohol are major factors.