I start by finding out where the difficulty actually began. A GCSE student stuck on algebra is usually missing something from primary; an A-Level physics student struggling with mechanics is often fighting the maths rather than the physics. Drilling past papers over an unaddressed gap wastes everyone's time, so the first session is diagnostic, a short assessment and a conversation about what feels hardest.
From there I build a plan around the specification, working from the underlying idea outward. I ask students to explain their reasoning back to me, because being able to follow a method and being able to use it under exam pressure are different things.
Because I use this material as a working engineer, I can answer the question every student eventually asks: what is this actually for. Calculus, forces and thermodynamics aren't abstract topics I revised once — they're things I work with, and students engage differently when that's clear.
I'm also honest with parents. After the first assessment I'll say plainly what I think your child needs, including if that's fewer sessions than expected.