For science - structure your answers and notes as you would in an exam, they'll never ask you to write essays, and normally when you answer questions you can answer them in dot point form, that is one point then another then summarise it fairly quickly.
Maths - nerh, do your homework, and when your school provides past papers, do them, that's all you need for year 11.
english - fuck it, don't bother (bias hate for english)
For year 11, it is a good thing to get into the habit, but don't let good marks make your head big, as nothing contributes to your HSC.
And for the last time, Year 11 does NOT count ANYTHING in your HSC. The content will be examined on (only a bit) but the marks gained in year 11 are nothing but indicator of how you can improve.
Good look fellas.