How to write better biology essays for AQA

Teachers in my school advice 4 well developed paragraphs plus a brief introduction and conduction.
I have wrote 4 essays as a practice and the general feedback is
-lack of A level content/terminology, linking is getting better but still needs to improve, some points may be irrelevant to the essay topic.
marks I got is generally in the 11-15 band, or sometimes 1-5 if one of my paragraphs is irrelevant.
Also, I struggled to write them in timed conditions, it took me 30 minutes to plan and at least 1 hr to write the essay as I still need to try to make it make sense,
Therefore, I would really appreciate advice on how to decrease the time spent doing the essay as well as improving on how to write decent relevant paragraphs with good A level Terminology, thank you and I am really struggling and I am very worried.