In the IELTS test, grammar is awarded a separate band score in speaking. There are four sections to the assessment criteria. The first is Fluency and Coherence. This means how easily and clearly you are able to speak. The second is the Lexical resource, which concerns your vocabulary.
Of course, another assessment criteria is pronunciation, where stress, intonation, and saying words correctly are important. The fourth of the assessment criteria is grammar.
You will need to do well in several areas. You’ll need to have a mix of complex, compound, and simple sentences. You’ll need to apply the right tenses and word forms in the right situations. You’ll need to be accurate. And finally, you must use your grammar to express your ideas clearly.
A great way to truly improve your spoken grammar is to truly learn the rules. Take the time to read and understand why grammar rules exist.