[bread_baker]

Hi Leena,
It may not be you at all. I've been teaching Beginning High in California for 3 years. Some students did not get much (if any) education in their native countries, and these students find it very difficult to learn English. Some students are hands-on learners, and they MUST have hands-on activities in order to learn. Other students are visual learners, and they need visual activities.
If you have time, you could read an article or a book about learning styles or multiple intelligences (these are pretty much the same thing). This information will help you understand how to create more effective lessons.
Other points to consider: do the students do their homework? Do they study for the tests? Are they really in class because they want a social activity?
If the students don't do their part, or aren't motivated, that is something you can't control.