Build the week around the test dates. They are set by someone else, months in advance, and every other slot has value only in relation to them — a school that treats them as just another appointment ends up with learners peaking two weeks late.
Keep the progress record with the learner. Instructors get ill, learners switch, cars go in for service, and the difference between a smooth cover lesson and a wasted hour is whether the next instructor can see what was already done.
Track prepaid hours as a liability rather than as income. Ten hours sold in January and given in June is work still owed, and a school counting that money as profit in the spring is the one that struggles in the autumn.