Quality Over Quantity Many parents make their kids do 50 practice papers. The child gets 20/35 every time. They aren't improving; they are just practicing their mistakes.
The Magic Step: The Error Log After every practice test, do not just count the score. You must spend more time reviewing the test than taking it. Create a spreadsheet or notebook with three columns: The Question: (e.g., Q14 - Fractions). Why I Got It Wrong: (e.g., "I rushed," "I didn't read the unit change," "I don't know how to add fractions."). The Lesson: (e.g., "Always convert to the same denominator first.").
The Rule You are not allowed to take a new test until you have fixed the errors from the last one. If you don't know why you got it wrong, you will get it wrong again.