Hi! I'm in the starting Year 10 in 2022 as well. I plan on doing VCE German, VCE Biology, VCE Chemistry, VCE Methods, VCE Specialist Maths and VCE English in Year 11 and 12. Any tips on self-studying for a language?
Hello there! I'd be happy to give you some tips on self-studying

SELF-STUDYING A LANGUAGE:
1. Motivation. I repeat. You need motivation. Otherwise giving up on the routine feels like a cycle, it quickly becomes exhausting and hard to do. I found I had a lack of motivation when my routine was too intense and too notes based and not goal oriented as such. I was studying from random sources that had no relevance to my goals. Which leads me to my next point.
2. Make a schedule of different sources to study each day, but it can't be intensive. An intensive schedule will lead you to be quickly exhausted. I did it for months and it did not work out. If you go too intense (especially from the start) you'll burn out very quickly for a very long time. So I recommend either scheduling smaller things everyday (if you want everyday practice) or scheduling actual study once every two days and a tiny daily routine for German that you keep to on the side.
3. Immersion. Immersion is extremely important and vital to learning a language. Things like (in your case) listening to German podcasts, reading German news or books, watching German videos, etc. Things like listening to an episode or two of a podcast in your target language every day on your bus commute can really increase your listening skills. It doesn't have to be too big or anything. For a long while, I didn't focus on Japanese immersion, I focused on intense memorisation and the consequences of that were that I would recognise things but forget what they meant or how to use them and I would forget the word whilst listening to Japanese stuff. You can also watch German TV shows and movies. There are channels on YouTube that do podcasts (I'll link some at the end of this reply)
4. Don't forget grammar. I know it's easy to get caught up in vocabulary and such, but grammar is vital as well!
5. Just a recommendation, not a requirement, but: install Anki. You'll thank me for it later. It's an app where you put flashcards in and you go through them each day with only a certain amount of new cards each day (and it'll give you a certain amount to revise) and you choose how easy it is and based off that, that's when the card will appear again. It's great for long-term study, so basically any vocab words you come across that are new (in reading or something) you can search up and add to your anki deck to learn later. It's a bit like an online dictionary. You can install it for free on your laptop or pay to install it on your phone.
6. Speaking practice is so important. Some forget about speaking practice (and listening practice) but it's equally vital and so important. Please don't forget it.
7. Take breaks when you need to. Establish healthy boundaries with your studies and don't persist when you're tired. Schedule in breaks in your head as a matter of fact, if you study without rest, you'll be exhausted and not have time for much else.
Some good resources for studying German (I presume that's the language you wish to self-study):
https://www.youtube.com/channel/UCbxb2fqe9oNgglAoYqsYOtQ - A German Podcast for beginners that I found that seems promising (I don't know how advanced your school's German education is, so I'll include something for intermediate learners as well)
https://mydailygerman.com/websites-learn-german/ - A list of good resources for beginners, I recommend checking out resources 1, 3, 4, and 10 as they seem rather promising.
Also do check out atarnotes' VCE German SL section, I haven't personally seen it myself but there will inevitably be some amazing advice tailored to German or some amazing resources that will really help you!
Good luck on your VCE journey!