For both science writings make sure you know a proper structure that you can easily adapt to any stimulus. You are basically guaranteed a sup if you work on this early enough.
Extremely simplified guide:
SIC
Intro - 3-4 sentences (background/context, problem or concept of the topic, key points discussed in your bps -- if yk the upside triangle thing for intros then you are good)
3x Body paragraph - 3-4 sentences (you are given questions to answer throughout your piece so just assign a question to each paragraph) use TEEL as make sure you are using facts and statistics from the stimulus)
Conclusion - 2-3 sentences (just concisely summarise the whole thing, state the central point of view and like whatever you feel belongs here -- assesors dont really care about the conc, it is just required for structure.)
The whole essay does not have to be long. I practised forcing myself to be more concise (they give you three pages to write on, but using two is the sweet spot.)
I'll write another one of SAR soon. (hint: you'll probably need to re learn how to write a report JMSS style 😉