I'm recently single out of a 7 year relationship.

I need advice picking up girls, I work as a teacher of a hobby, so not college/school.

I teach many pretty girls who I would love to try and pick up.

My issue isn't approaching or talking to girls, and having a conversation isn't too tricky either.

I need to find a way to show I'm interested in them as a relationship and not just talking to them because I'm paid to be talking to them as a teacher. It needs to be fairly subtle because I am there in a professional capacity. any ideas?

I could also do with learning how to figure out if they are interested back rather than just talking because of me teaching them.

Open suggestions of books, videos or whatever else on getting me started here.

I'm trying to give a lot more eye contact when talking, smile more, and use their name often. What else can I do?