Ok.
So, the best things to do are:
Familiarise yourself with wherever the interview will be taking place.
It's positive that you had a chat with the Receptionist.
Research as much as possible i.e. look in-depth at the school website, social media and whatever trust it's incorporated into (I can't say anything about teaching specifically as I have no idea!). Try and mention that you have done this.
Do you take in a copy of your CV or application with you? It's handy to refer to and shows you are organised and have the know-how to plan ahead.
If you do think you've missed out on explaining something, ask the panel "Is there anything you'd like me to expand on?". Then they should say if they think an answer to a question needs more depth. That's a really important thing as if they are scoring applicants using a points system, you not only get points for engaging/asking but you get the opportunity to go back and attain extra points on something you haven't touch on.
Relax. Be confident. Remember everyone else is there for the same reason.
It's a 'numbers game' really. You can even ask how many applications were shortlisted to be interviewed.
Before they phone you with feedback tomorrow, make a list of things you want to ask.
Good luck. You can do this. Sometimes it just takes a while. You will get there.