As @thetestdude mentioned it doesn't count towards your HSC marks.

I strongly recommend the following few tips for any Year 11 student:

Familiarise yourself with your syllabus

Basically the syllabus is your bible
Try to study the syllabus, analysis how its structures, look at the terms & terminologies are being used.
Start incorporating syllabus points when you are making your study notes

Take Year 11 as a year of experimenting, you won't have a chance in Year 12 to experiment.

Try to figure out what works best for you,
By choosing a study style which suits you
Like does palm cards or mind maps work for you
Figure out what subjects a bit more difficult for you & which subject require that much of your time.

Read your prescribed text in Advance

If you read your text in advance it really does help to cut down that stress and the amount of work.
With the less work overload it allows to understand the text better

Have a balance

Year 11 counts if you want;

To apply for scholarships, cadetships, early entry and etc
Sometimes applications will come out middle of Year 12, so somthimes you' wont have your year 12 report ready, so they will ask for your year 11 report.

Participate in as many extracurricular activities as you can possibly

Like when applying for early entries, scholarships even part-time jobs a lot of employers and a lot of universities will be looking to see what more do you do outside of just your schooling
With these activities you will learn key skills like leadership communication, things that you won't learn in the school/classrom

Establish goals

Have goals so that they guide how you're gonna approach your 11 like if your goal is to become more confident speaker by the end of the year, then enroll yourself in like debating and public speaking.
Have goals that you have a path and a clear structure on how you're gonna take on year 11.

Also, you could check out @HiteshDhawan's article on the first week of year 11.