When I have previously taught my siblings and friends, it's usually best to take a patient approach. Ergo, I would first ask for what the student already knows, to write their own answer to an exam question so I can see how they write and approach it. We would go through a mark scheme and various examples to see what to poach in their own answer, and how to mould and write it in a way that feels natural to them. We would continue this until the student makes progress with their answer in a way a top student would.