My lessons are student specific working on topics the student feel unsure on or topics I discover need work using a past paper or end of year assessment. If an assessment is necessary this is usually done within a session and has no pressure for marks it's just for me to see were they are struggling. I often use worksheets swapping between overviews of topics and worksheets on specific subtopics depending on the students need. I also don't move on until the student feels confident to do so allowing multiple chances for them to ask questions or get alternate explanations or methods for topics. I feel confidence building is an essential step to improve mathematical ability.