I often have the same problem. Over the years I have found that you really have to divide some of your lessons into stages. As I am a high school English teacher, this is just one example of a lesson I have listed. Other lessons would take the form of grammar exercises/tests, debates about current issues. Watching & discussing relevant films/ documentaries. Analysis of media articles, assignments with a choice of questions using Bloom's Taxonomy on different aspects of novels/ poetry, short stories etc. Weekly quizzes run by the students based on the topics you covered in class with simple prizes is popular.Time in the computer rooms and library is also allocated for research. It depends a lot on your school's resources of course. Here's an example of a lesson involving all students:
1.Explain very clearly by saying and writing on the board what the lesson is going to be about. Example : themes of a novel
2. Set a task for students to work in pairs of groups of 4[ change the groups each time] Example: Give each group a different theme to explore.
3. Give the students 10-15 minutes discuss & complete the work. They can write their answers on a big sheet of paper which can be displayed in the classroom after a lesson.
4.Each group reports their results to the rest of the class.Reward the best answers by praise/ special stickers/going to lunch 2 minutes early etc.
5.The students then work individually on the next task you set. Example: Plan and start writing an essay about which 2 themes they thought were the most important in the novel and why. Use quotes and examples from the novel in their essays.
6. Before the end of the lesson, recap what you want them to do, for example finish their essay by a certain date or do more research about the characters in the novel.