Ideally, we can engage their curiosity and enthusiasm in ways that lead them to do the work because they want to. Good practice communicates high expectations. A few students always exceed our expectations, a few dramatically fail to meet them, and most pretty much achieve what we ask of them. Within limits, then, raising our expectations and communicating them effectively raises our students' achievement. Knowing just how high we can realistically set our expectations requires knowing our students.
Experience helps here, and so does data gathering.
We have two different kinds of opportunities. First, we can communicate expectations by what we ask of them. Second, when we provide feedback to students, we can honestly let them know what they have done well and where we think they can achieve more. Good practice respects diverse talents and ways of learning. Students differ along many important dimensions.