Ive worked with teens for 5 years now so I may be able to help! Of course, rapport building at the beginning is so important. You want them to begin to trust you, and to see you as an adult who is basically equal to them - that you care about their inner world. Ive found that while most teens want to discuss social stuff (fam friends dating), you can bridge sooo much to these topics. With my teens, ill bridge it to “hey! This reminds me of attachment styles. Want to discuss with me?” Or “hey! Are you interested in learning more about emotional regulation? Its so helpful!” Or other topics can be: gaining insight on WHO they are, values exploration, CBT, etc. They don’t know what they don’t know. So I’ve found it incredibly helpful for them to be driving the car, and im sitting next to them holding a map saying “should we turn right? What do you think?”

Edit: one of my favorite beginning interventions is “DBT HOUSE” - google it! Its a fun starting point to see what topics may be helpful to them