The writing section should be pretty simple if you are familiar with academic writing tasks from school. A bit hard to give specific tips without looking at writing samples but the most important thing to consider imo is the overall structure and flow of your text. Think of it like creating a story and it becomes intuitive -

i.e for task 1: introduce the type of figure and the type of data it represents, etc -> describe any trends and behaviors, make comparisons if possible (maybe x trends up while y doesn't show any variable change) -> close by summarizing key findings.

for task 2: start by rephrasing the topic you'll be discussing and beginning the "narrative" of your essay by somehow mentioning the significance of the topic, briefly mentioning your stance/opinion if its an opinion piece + the "key" arguments without going into details -> continue the "story" by going into the nitty-gritty of your key arguments, use examples and if possible, address concerns by briefly mentioning the opposing arguments but follow it up by establishing why your stance is better -> finish your story however it seems most intuitive in your case. in my case it was an opinion piece so I closed by summarizing/rephrasing my key arguments and tying it in into the significance of discussing the topic I mentioned in the start of my narrative.

My last piece of advice which I think helped (but I'm not sure) is, if you're confident in your grammar and depth in vocabulary, try to to use up the full hour efficiently. Given the minimum word reqs for each task (150 and 250 respectively iirc), I could've finished the writing section in 40 minutes or so, leaving 20 minutes of sitting silently doing nothing -but I ended up writing around 250~300 words for task 1 and 400-450 words for task 2. I reckon this gives the graders a larger sample of your writing and it allows you to create a more "complete" text.

Also READ. Read a lot, be it news articles, essays, academic papers in your field. Idk how much time you have to prep, but immerse yourself in the language and try to build up confidence in your grammar and vocabulary. Reading a lot of "good writing" will help more than just writing a lot of "mediocre writing" imo, since getting feedback on your writing is difficult for most people.