Balance is visible in a table
List chapters down one side and question types across the other, then place the proposed marks in the cells. The table makes overrepresented chapters and missing skills easier to spot than reading the paper from top to bottom.
Match demand to marks
A one-mark question should not require several unrelated calculations. A long-answer question should justify its marks through explanation, reasoning, construction or interpretation rather than length alone.
Estimate student time
Solve the complete paper and then allow additional time for reading, thinking, writing and checking. Students work under different conditions from the teacher who prepared the paper, so author completion time is only a lower bound.
Run a final fairness review
Check that required knowledge was taught, the language is accessible, diagrams are legible and internal choices have comparable demand. Remove accidental clues between questions and verify that translated versions ask the same thing.