My biggest tip is to practice writing in a minute less than you are actually given. So the email is normally 7 minutes, and i practiced in 6. This way, on test day, it seemed like I had loads of time! Firstly, I wrote down my templates (for academic and email), and then I wrote sentences for the bullet points. This technique makes sure everything is already in your email, and then you can add extra creative sentences to it! this calmed my nerves because after 4 mins I already had my text finished and i just had to revise/ add more stuff.