For guidance, support and encouragement

To act as a role model

To give honest constructive feedback

To build confidence

To make theory practice links

To carry out assessments in practice

To correct/prevent unsafe/poor practice

To direct learners towards learning opportunities

The list is not exhaustive and you may well have thought of others. Looking at the list you can see that it covers knowledge transfer, practical support and guidance, assessment and competency, as well as helping the learner to make the most of the learning environment.