Vocabulary range is not a competition to use the rarest word. It is the ability to choose precise language, combine it naturally, and adapt it to the task and register.
Collect collocations and patterns
Save the phrase around a new word, not just the dictionary definition. Notice whether it takes a particular preposition, noun, verb form, or level of formality.
Retrieve before you reread
Cover the answer and produce the phrase from a cue. Then write or say an example related to a topic you may actually discuss. This reveals whether the language is ready for communication.
Choose precision over decoration
An accurate familiar word supports clarity. An ambitious word used with the wrong meaning, grammar, or collocation weakens the message. Expand range by protecting control.