I try to make my online lessons as cosy as possible. I use the video-conference system, so I can see my students and they can see me; we can talk, we make the exercises together, I explain all the grammar, and if my students have any doubt or questions, I explain it orally which I think makes it easier to be understood.
It is as if we were sitting in an office side by side. The only thing we cannot do is drinking a coffee while we study.
Besides the lessons, I always send some homework. I will send a book that we follow, and the rest of the material is sent by me by e-mail as well.
As soon as it is possible, I advise my students to start reading books in the language they learn, and from the very beginning to start listening to the TV. It is a way of being surrounded by the language.
I always insist a lot on the accent, and this helps. I have students with a perfect accent. Listening to the language also helps to open the hears to the sounds, making easier to understand. From the very beginning I also start with small conversations in each lesson.
You may believe that all my students are being very successful with this kind of lessons. I have now students from all over the world. Concerning the level my students attain, ofcourse it depends on them.
Together we see what your needs are and how fast you want to learn.
As for the number of lessons per week, I advise that you should have at least two. Less than two is very little and you have a long break between lessons. It is bad because you don't have any contact with the language and feel that you are advancing very slowly.
I am a qualificated teacher in Dutch language and have been teaching for more than 20 years at school and online, groups as well as lessons.