Hi! I'm a teacher from Russia. I think that the main problem isn't in your PP presentations. It's in motivation and involving your students in process of teaching. Your students must work actively during the lessons, solving a lot of problems, both hard and easy ones. It makes them thinking all the time and they will see that all your presentations aren't only a number of slides with info, but full of smart logic riddles and tasks with some mysteries. You, as a teacher should find or make up such tasks and exercises for them. Then I'm sure, the students will visit your studies as it's more interesting to find out facts themselves than to be passive at lessons and they'll consider that they've known new material themselves. But you, only you, with your tactics and strategy as a teacher will be able to do it.
Sorry for explanations in general, as I don't know exactly your methods of teaching with the help of PP presentation. If only I knew, I might do it more detailed.
Faithfully,
Irene