Thank you, Lea and Murillo for your comments!

I want to try offering instant tutoring next week. I will see how it goes and remember to take your advice and help my students talk for most of the time (or help them when they get stuck).

It should be for informal conversation or to answer specific questions. Or even in cases where the student sends a message before saying what he orf she would like to work on (it's up to you to accept or decline the request). 

Teachers don't need to prepare anything but would be nice if the teacher knew how to lead a conversation, avoiding those awkward seconds of silence is the key to make the student feel comfortable and satisfied. 

And rule number 1, always allow the student to talk most of the time. It's disappointing when I order an instant tutoring session and I get to speak only 10 minutes out of the 30 ones. 

Hi Sabrina. 

I've never took an instant tutoring sessions. I never noticed before or found out what is the instant tutoring. So this is the first time I understand what it is for. But I hope you wouldn't mind if I try to give my opinion as a student. :)

I think if I wanted to take a intant tutoring session, I would prepare my self first what kind of topic I'd like to talk about with my teacher wannabe. I'd make a list about the questions or statements according to the topics that I pick. Of course the topic that I choose should be a common or general topics.

I think what you should prepare is if your student is not really ready to talk with you or her English is too bad (like me, sometimes I got nervous or panic when I couldn't answer the questions) my teacher would change the question. 

hope these are useful. :)