how can you achieve 7 in IELTS.You have to practice and practice. The hardest part is the reading comprehension. You have to time your reading and try to find the main idea,what the passage try to tell you,what does thing in ply in the passage. Then practice writing. The Ielts allow you 45 minutes so you have to practice writing then try to make thing simple and concise. Also try to wrap thing up within 30 minutes/35 minutes. By doing so you have approximately 10-15 minute to revise and rewrite your essay.
The easiest part for me is listening and speaking which I think everyone can perfect the score.