A useful way to think about English in speaking tests is to divide your language into two types. One type is the actual information you want to give, the other type is the phrases that you use to introduce, support or link your information.
I call these categories ”meat” and ”potatoes”. The meat is the main information and the potatoes is the supporting language. The good thing about potatoes is they go with all sorts of meat—that means you can use potato language in any answer, regardless of the subject.
Here’s an example:
Question: What are the pros and cons of living in a foreign country?
First of all, let me look at the advantages of living in another country. One of the main positives of heading overseas is that it broadens your horizons. What I mean by this is that you have the chance to meet people from different cultural backgrounds and learn to cope with foreign customs and food. This can make you more well-rounded as a person.
The supporting language, the potatoes, are in italics. Let’s see how these phrases can be used in an entirely different context.
Question: What do you think about working from home?
First of all, let me look at the advantages of working from home. One of the main positives of working remotely is that you don’t have to travel to work. What I mean by this is that you can avoid the rush hour on the way to the office and start work more quickly. This can improve your performance immeasurably.
As you can see, potato language is the same in every answer, so as long as you understand the function of each phrase, you can use it in a myriad of ways. For instance, "what I mean by this" performs the function of clarification, so you use it every time you want to make a point clear.
It goes without saying that having several ways to perform the same function will enrich your answer, so once you master this one, work on another phrase that has the same function to avoid repetition. Ask your teacher if you need some suggestions!
broaden one's horizons—to expand one's range of interests, activities, and knowledge.
well-rounded—having a personality that is fully developed in all aspects.
myriad—a countless or extremely great number.
clarification—to make information clear by repeating it, typically using different language.