This is a question, we get asked lot of times and while there are general guidelines which would help every student, there are many factors which affect the performance in the IELTS exam.
Below is the general guide which would help every student improve their overall score in IELTS.
IELTS is a test of your English, so a key step to have good score, is to improve your overall skills in English. If you have time, then the easiest way to do this is to join professional IELTS coaching institute such as ours to improve your English skills.
Use English as much as you can in every day situations, try speaking English at home and with friends etc. to improve your speaking skills and understanding of English in General.
To improve your listening skills try listening to English documentaries such as shown on Discovery channel , listen to news channel such as BBC , CNN and furthermore, watch English movies and listen to English songs to get used to native English speaker accent, which would help you in big way to improve your scores in IELTS.
Read magazines with scientific language such as National geographic, Scientific American, The Economist etc which have little academic bent to their articles , this is because the texts you would need to solve in IELTS reading exam are of academic nature ( if you taking Academic module of exam) , this would help you in improving your reading skills.
To improve your writing skills, you need to start writing emails, letters, and study the structure of formal letters and essays which is provided in the IELTS preparation books to understand as to what makes a better answer, furthermore, you must try practicing the IELTS writing by writing essays and exam letters/ reports regularly to improve your writing skills.
You must understand the test format fully in order to score well on IELTS exam , especially time management is very crucial in IELTS Listening, Reading and Writing. Also you should know that you must write atleast 150 words in First writing Task and 250 words in 2nd Writing task, you should know how to count the words and also the fact that if you copy the question on to answer sheet , it does not form part of answers that you write and so on.
Furthermore, you must follow the instructions carefully as given in the exam, usually we notice that valuable marks are lost by students because of careless mistakes, for example, when Question instructions say “ Write no more than two words” or “ write answer from the passage” , we notice students write more than two words and writing words that do not appear in the test passage.
Most important step is to practice with lots of mock exams under the guidance of trained IELTS teacher, so as to have real exam feel and feedback about mistakes and how you can improve your score even further.
Some test takers have generally good level of English, however it does not mean that they would score very high, because, IELTS is still an exam and one must understand the exam format and learn strategies to improve their score.