What do you plan to do? I can't believe already you next lot are ready to start your major works! Good luck for the whole process, it's very rewarding and make the most of it.
The best things to do is to visit the 'Major Works' thread in BOS ee2 forums.
http://community.boredofstudies.org/608/major-works/
I believe it is divided up into years. Make a look out for 'What shall we do Tomorrow?' by Super_katie. It's fantastic and it got 50/50. Another major work I liked was 'fusions'. There is a range of standards, so be open-minded.
Try this link
http://ashlee.8k.com/shadowsfalling/
and visit her guestbook. no offence intended, but learn from her mistakes. That is be weary of people's praise. It's all well-intentioned, but it can make you too complacent etc. One should seek harsh criticism, continually.
Another thing to do is to read all the showcases form the past years. They are anthologies of the absolute best of the best (or best suited to the anthology) that recieved 50/50. They are there to present the standards of the best. So other can aspire towards them. My favourites are 'Hawk from a Handsaw' and 'Paper SKin'. And from last years 'Young Writers Showcase 2005', 'Poetry-Shaped Photographs'. Your school or library would most likely have these, otherwise maybe you can order them.
And the other thing is to visit boardofstudies.com and go to their Assessment Resource Centre, and click on the 'Standard Packages' link. Then click on ee2, and you can read major works that got the lowest band up to the hightest. It instills a lot of confidence after read band 1 major works, lol.
But the bottom line is that although you can develop as a poet and writer throughout the HSC year, you should hold some degree of innate talent, which I'm sure you have. A love for words, and a passion to write. Its a different path for everyone, but it is hard work. And also, you may want to attend poety events, festivals, etc. They are always good.
After reading all the past major works, broaden yourself by reading quality published poetry. And find, maintain or develop your own voice. Never ever go "oh, i must write like this to get 50/50."
You wanted to know what standard to reach, but honestly just do your best. keep reaching high. high above the A-range. I'm not saying have high-expectation, but keep trying to reach your potential.
Lastly, enjoy! Keep it fun and real and then you'll finish ee2 with a smile on your face!