I’m an A-Level student studying Mathematics. I am really confident at teaching maths as at GCSE Maths I got a 9 and basically full marks as well

Start by finding out which topics from the specification the student needs work on first. Will teach the easier and harder questions for each topic. First student can say what they know, then I will show how to do it, then let student try one together before letting them do some on their own.
Every lesson will start with a couple questions from previous weeks to make sure they don’t forget it. This is the method I did to get my Grade 9.