Speak and write with confidence.
To help you avoid using the same word too repetitively, redundantly, recurrently, incessantly, etc., etc.
Your writing can sound boring if you continually keep repeating the same words. When you create sentences, you can make them more interesting by using words that mean the same as the word you are speaking about. This allows you to add flavor to your writing.
In order to make language a lot more expressive and interesting you should try to vary the words you use as often as you can.