A lot of people ask me what they should do to improve their scores. Generally speaking, there are only two things that you can do:
- Work on your exam technique
- Work on your English
I can often help students to make fast improvements by teaching them how to organise their essays, how to look for keywords in the reading test, or how to expand their answers in the speaking test. These are exam techniques.
However, exam techniques alone will not get you a band 7. You need a good level of English to get a 7, and that means you need to do the hard work it takes to gradually learn more words and phrases, improve your speaking fluency, and generally become a more confident user of the language.
Point 2 takes time. Don't expect your English to improve from 5.5 to 7 without a lot of work!