First of all, familiarize yourself with the test format for all the 4 papers.
Then do as many practices as possible, especially for reading and listening papers.
For writing, read more sample passages and practice. Try to make good use of keywords for your target score.
For speaking, if you can't find someone to practice with you, record what you say and listen to your intonation, phrasing, flow and so on, and try to improve.
To start with, you can try writing down your thoughts in point form without setting a time limit for yourself, then read them out slowly and see if you can generate complete sentences with your written points.