Spend more time focusing on the type of questions you will be possibly asked, you will find it a lot easier to succeed!

Pronunciation

Stress/intonation

Use big words; pronounce them properly and in the correct context.

Use a variety of ways to describe different tenses and try to use higher level grammar.

Simply put, if you become more fluent you become more natural, like a native speaker. The more like a native speaker you are, the higher your score!

The fluency part of the speaking test is actually called fluency and coherence. To simplify, fluency refers to how natural you are and coherence refers to how clear/well organized you are.

Structure refers to your ability to organize your thoughts, opinions and examples in a clear, well-presented way.