IELTS Exam; essay part, intro, every related information

Need a help from you people what should i focus on while doing essay part because i m afraid of giving exam..
i m really facing so much problem how my intro should be
is vocabulary is needed good for scoring approx 6.5 Bands ?
please give me each and every information related to this guys
what type of essay it shoud be >
i m waiting for your reply guys

Well, you need to have a good essay structure, good grammar and clarity in your sentences, good flow of ideas and also display your vocabulary skills to get a good score. But , displaying vocabulary knowledge does not mean you should try very advance words (going by the synonyms) in your sentences if you are not sure of their exact usage. You can even express your ideas with simple words you know and that is much better than using unknown words and confusing the reader.