Apart from working hard to remember all of the content and practicing the questions there's not a great deal more you can do.
However, learning all the stuff paying close attention to detail can pay off - the difference between a B and an A can be a few little words missed out. Mark schemes for Biology past papers are really helpful because a lot of content in biology requires remembering stages of processes. If you use the mark schemes and memorise the stages succinctly as they're set out in the MS this should help. One line equating to one mark missed out on every 3+ mark question for example soon adds up and can cause the grade drop.
In short: make sure you're happy with the basics and the majority of the content, then use mark schemes to identify phrases and words the exam board likes and gives marks for.