I only get score 5 or 5.5 in IELTS. How can I get better marks?

I want to get good band score in writing task but I didn't get good band score I did always get 5 or 5.5 only what I do to score good band score please help me and give me valuable suggestions I did my IELTS test 4 times but I wasn't scored good band score I am so frustrated give me your valuable suggestion in all tasks like reading,listning,writing,speaking in IELTS I hope you will give valuable suggestions to me.