Even though I started to shift the focus in the classroom: from myself (the teacher) to the students, it is still difficult to involve every student in learning. Some students are too lazy to use their brains and refuse to cooperate, either in groups or alone.
Activities are not a panacea: I should have in mind “what skills students are expected to acquire” before planning any activity, not the other way around.
Keep students busy, but in a meaningful context. Always bear in mind the “BIG IDEAS”.