The chance of getting the score you want in 15 days to one month is pretty unpredictable. It all depends on the current level of English proficiency, your hard work, focus, and dedication.
If you currently have a high level of English proficiency (Band 6.0 - 6.5), you just need to accumulate and learn some proper techniques, tips and apply to practicing tests daily to get the score you need (Band 7.0 - 7.5).
And If you are the beginner, you should focus more on it. For example, your IELTS Reading score is 5.5 while other skills are over 6.0, you should get down to improving your reading skills by taking IELTS coaching from any proficient person having expertise in IELTS tips & tricks.
The road to IELTS test drive:
Listening Section:
Make sure for the listening section you pay attention to every detail of the conversation. Often it isn’t that you didn’t hear the conversation, it’s just that you aren’t focused.
Reading Section:
You will have a lot of time for this section generally speaking. Be sure to make the most out of it. If you are stuck on one question go to the next. And I'm sure you are troubled by the fact that not given/false are extremely similar. The truth is, it isn’t. Don’t interpret the passage. Rather, look for evidence as questions are always evidence-based. If you can’t figure out why the statement is right or wrong 90 percent of the time the answer is not given.
Writing Section:
I’m not well qualified to speak for this section. However, you should definitely spend more time on Task 2 than Task 1. For task 1, don’t write down every detail. Be sure to note down the significant trends and relationships between two graphs if there are two graphs/diagrams. Also, use a variety of vocabulary when describing degrees of change. Here’s a list of words that you can use: minimal, slight, gradual, moderate, considerable, significant, substantial, enormous, dramatic.
Speaking Section:
Practice by recording yourself and at the end listen to your own recording to notice the inconsistencies and errors. Then you will gradually improve. I suggest you videotape you (it may seem like a stupid thing to do but it is an effective way). On the test day, go in the testing room with an assuring smile and be confident.
Remember, confidence is your best makeup. It is the key to great communication and impression.