The multiple-choice section is graded optically. Fill the bubbles completely with a 2B pencil. A dot or a check mark will not register. Extending a mark outside the bubble will not register either.
The free-response section is graded by humans who scan sheet images. Write inside the printed boxes. Anything outside the box is invisible to the grader.
You may not use correction fluid or tape on the answer sheet. If you make a mistake, cross it out cleanly and rewrite. Do not scribble.
For the essay, count characters as you go — most provinces require at least 800 characters, and running short costs more than the missing content.
Leave the last five minutes of each subject strictly for transferring answers from the question booklet to the answer sheet if you have been working on scratch. This is when the most preventable errors happen.