Being able to use a rich vocabulary is a major advantage in the IELTS and will certainly help you get a higher score. It will also be beneficial in your academic, personal and professional life. For example, if you wish to pursue higher education at university, research has shown that you may need up to 10,000 words.
There are a number of ways in which you can improve your vocabulary. Whichever method you adopt, you'll want to create a vocabulary notebook in which you write down new words and sample sentences.
DIRECT OR INDIRECT METHODS
Your strategy may be direct or indirect. The choice depends on your current vocabulary level. If you need major improvement, you should set up a study schedule which includes a specific time in which you work on learning new words and expressions. You could select one of the many excellent vocabulary enrichment books available today, or one specifically designed for the IELTS, which covers a number of different subject areas. You could work for as little as 10 minutes a day to as much as one hour a day. No matter how much you do, working steadily and daily will produce impressive results.
The second way is to adopt indirect strategies to enrich your vocabulary. This includes reading newspapers, magazines, textbooks, brochures, and fiction or non-fiction books. It includes watching and listening to news broadcasts, interviews, songs, documentaries, movies, audio books, and discussions. Not only should you write down the new words and their meanings, but also use the new words in your own written or oral sentences.
With such a wide selection of vocabulary improvement materials available, you can select the system you feel most comfortable with and enjoy the most. Identify the best vocabulary books for your needs at the local library, though friends, teachers, or online. If you have an auditory learning style, choose tapes and CDs. It takes time to build up your vocabulary so find a program which appeals to you and you'll stick with..
Along with general ESL vocabulary materials, there are general and specific IELTS vocabulary programs. General IELTS preparation materials address all the skill areas covered in the exam, and include vocabulary sections as well. An example of such a book is IELTS Masterclass by Simon Haines. On the other hand, specific IELTS vocabulary books are devoted exclusively to vocabulary enrichment. Examples are Check Your English Vocabulary for IELTS by Rawdon Wyatt and Cambridge Vocabulary for IELTS (with Audio CD).
Many ESL websites offer a wide variety of vocabulary building games at all levels and for various purposes.