Can I improve my score from 5.5 to 7 in one month?
The honest answer is: no, you probably can't
It's important to be realistic about the time it takes to improve your ability to speak, write or understand a second language. It's a really difficult task. There is no magic recipe for success and there are no shortcuts. Take your time, work hard and be patient.
I've underlined the good vocabulary contained in my advice.