Here's one technique you could use to improve your vocabulary for your IELTS.
The technique involves identifying certain words and determining the various word forms.
English words could have different forms, depending on how they are used. Particularly, a word could either be used as a Noun, Verb, Adjective, or Adverb.
Take for instance the word "manage." "Manage" is a verb. It however has other word forms. When used as a noun, the word is "management," or "manager." If used as an adjective, it's "manageable." And when used as an adverb, it's "manageably." Thus:
manage - verb
management/manager - noun
manageable - adjective
manageably - adverb
Let's take it a step further. Consider this sentence: "Martha managed the family business after her parents retired."
In the Listening and Reading modules, words and phrases in the exam booklet questions are expressed in a different way than those in the audio recording or reading passage, respectively. Thus in the recording or passage, you could perhaps encounter the sentence, "Martha was promoted to manager when her parents stepped down."
In writing and speaking on the other hand, candidates are not encouraged to copy the words as shown in the questions or tasks. Thus, let's say that you were presented with the following question: "Efficient management is an essential part of successful companies. To what extent do you agree or disagree." In the introduction one could write, "Effective business systems are composed of competent managers..."
To sum it up, add your knowledge of word forms to your IELTS skill set. These tips could be very handy for your prediction skills in listening, for your scanning skills in reading, and whenever you need to paraphrase with regard to your writing and speaking tasks. Do remember that lexical resource is a criteria checked by your examiners in writing and speaking. The more words you know and could use to your advantage, the better your chances of having a high score when you take the exam.
We hope the tips help.