The "main" HSC tutoring centres - Matrix, Talent 100, Dr Du, etc. all have English programs, but they mainly go through school content (not sure for Year 10 though?). That's probably not going to be helpful if you want to improve your creative writing specifically. I'd suggest staying away from group-tutoring if you want to improve in a specific aspect in English.
Private tutors are IMO better, you can find some here on this website, or on highschooltutors.com, or basically any other tutoring advertisment site. A lot of kids from my high school got their tutors from word-of-mouth, so that could be an option for you.
Since English is such a subjective subject, it's a bit hard to say who's "good" and who's "bad". I've been to tutors who got insane HSC marks and they've been crap, and tutors who did okay and have been great - so asking for a trial lesson yourself would be great!