It is a good idea to set boundaries with your students.
To start with, set their expectations at the start of a class. Ensure you explain what your class entails and the potential benefits they may see. Students can make informed decisions about whether to proceed with the class. Pre-preparing a class plan or sequence makes it easier. Briefly start the class with an introduction and run through the plan.
I recommend you take this a stage further and have information about what to expect before the class on your website and send it to them once they've paid.
You should have a professional relationship with your students, so keep your communication style professional. Familiarity could become a double-edged sword. Having a coffee with them may sound nice. However, it can quickly turn into you becoming your student counsellor. Trust me, I speak to many teachers and those who offer to help their students with problems promptly become free counsellors for their students, causing them to become burnt out!
You need to be energetic and grounded to be your best self and give your students the best teaching experience!