First time preparing and teaching a course I am a PhD student and I have been given the opportunity to teach a course over a three weeks period (2h per day, 30h in total) at an institution overseas. I feel competent in the field of the course I will be teaching, but in practice it will be my first time preparing and delivering a course (which is not the same as doing tutoring, or being a TA).

What strategies can I put in place to be an efficient teacher? In particular, I am afraid not to have enough materials to cover 2 hours of time for each lecture (but then I realize that if I am thinking that, it means I'll probably be waaayyy too fast, so that's not good). I am also afraid of being unable to read the classroom, and of losing the students' interest too quickly. 

Of course, I can prepare a lot of material to cover, then just go on my way, see where I end when the two hours are over, and start from there at the next lecture. But this might be too unstructured for the students, and I have very little time between two lectures to reorganize the material, since I am teaching every day for three weeks.

If you can share with me tips from your experience, I'd be very happy.
Rather than simply preparing material and plowing through it, I strongly recommend taking a "backward design" approach. You can Google that, but the basic idea is to start by thinking carefully about what it is you want students to have learned by the end of the course, and working backwards to what lectures, activities, and assessments contribute to this end. I've found this to be very useful, both for myself and for the students. 

As a general idea, keep in mind that teaching and learning aren't equivalent; it's easy to deliver material, but that doesn't mean that it's absorbed or understood, and it's worth thinking about what classroom activities make learning more likely. Your (present) university probably has some sort of teaching consulting group, who are probably worth chatting with. Good luck, and have fun!