In your essay you need to identify that goal. Give an explanation of how you plan to accomplish this goal. You should use your personal observations, expertise and skills to support your essay.
Don’t forget to add details and develop your ideas. Pay attention to sentence structure and avoid spelling errors.
Stay at the topic, and do not shift to less relevant subject areas.
Your essay must include a number of (preferably five) paragraphs where you explain to some detail how you reached your topic or conclusion.
You should begin with a clear main idea and support this main idea with three relevant paragraphs. End with your conclusion and use precise words.
It really depends on a number of factors, one of which is your understanding of the test and requirements of the band scores. If your English is suitable for the band score you are aiming for, you will only need to focus on exam skills to make sure you reach your potential. The skills will help you understand how to approach questions and what the examiner is looking for in your writing and speaking. Once you feel comfortable with all that, you will have a clear idea of how long you want to practice before your test. Whatever you decide, make sure you are frequently getting the band score you want in practice tests.
All the best