There are two important elements to consider in order to improve your essay writing. First, thorough knowledge and understanding of each module as well as your prescribed texts (including themes, quotes and techniques) are essential. This is because they constitute the foundation that you will rely on when writing an essay. Without thoroughly knowing and understanding the modules and texts, the quality of your response will be restricted. Good quality notes (which can be your own notes and/or notes made by someone else) can help you in that regard.
Second, substantial practice is important to reach a level at which you can consistently write essays of high quality. Completing practice questions will allow you to apply the knowledge and understanding that I mentioned earlier to different questions and in turn develop patterns that will allow you to think of ideas much faster, thereby helping with time management. This will be especially effective if you do not plan to memorise and regurgitate your essays, that is, if you aim to develop a unique response to each question that you attempt, as opposed to writing the same response to each question with minor modifications. To determine whether you are gradually improving as you practise, it would be good to request feedback from your teacher and implement any suggestions that they might offer.
I hope this helps!