Noraa "work over-time" means to do put in a lot more effort compared to someone else to compared to someone else. Like in a job, people sometimes work overtime hours to get extra pay. for year 10 jus do practice test and like critically analyze your thought process and desicion making skills during tests.
Read a lot more, and consume media(videos, articles etc.) that use intricate words, like sometimes I watch politicians debate, and when they are debating I hear words that I have never heard of in my life.
for maths jus go through the basics of year 8-10, they care more about accuracy and time management compared to raw intelligence. Numerical is jus problem solving skills, but the patterns are ez.
writing is pretty difficult, they changed the format for next year, so writing is 15 minutes with 5 minutes extra for planning. idk how to help you with that cus I'm UTTER GARBAGE at speed writing.