High school is rather a difficult stage to define. On the one hand, students of that age are usually not treated as if they were children, teachers try to instill as much responsibility and reason in them as it is possible. Controversial issues are no longer hidden; on the contrary, they are being revealed all the time.
Here you may see what in general high school academic writing is supposed to be like:
In essay writing students are supposed to start dealing with more general topics. In the middle school a typical essay topic may be something like “Should students be allowed to use cellphones at school?” High school, even dealing with the same topic, will offer something along the lines of “What is the influence of cellphones on our lives?”
A high school essay is usually not very long, about four-six paragraphs, giving only the necessary information. The basic structure is usually like this: introduction paragraph, three-four main body paragraphs and the conclusion.
At this point of education, the student is supposed to conduct a certain amount of research about what he is writing. If it is a book, he or she is supposed to read it and make notes. If it is a topic, he or she is supposed to read some literature on it.
Some topics are chosen by students themselves, some are imposed by the teacher; usually, they follow the general way of the class studies.
Although students are supposed to already have mastered the spelling, it is still very important to keep an eye on. Don’t be too dependent on various text processors.
Teachers expect students to start dabbling with more mature topics and by the end of the course to have a rather definite understanding of how they see their future lives.